overhydration or too little sodium you make the call :)

andy, you reading this? the evil wing of the ex-fizzers and armchair quarterback doctors are winning the battle for hearts and minds. but, at least they're doing their part to stop all those hyponatremia deaths that occur annually, like clockwork, during marathon and ironman season ;-)

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Dan Empfield
aka Slowman

It's overhydration. Go to medline, look for some of the recent work on the subject (noakes, speedy, etc) and follow the paper trail.

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Dr. Philip Skiba
Scientific Training for Endurance Athletes now available on Amazon!

Some trainers and sports physiologists contend that by the time you’re actually thirsty, you have lost enough fluid to already be dehydrated, so they say you need to drink in anticipation of becoming dehydrated, Verbalis explained. “We dispute that notion," he said, "and contend that thirst is a good indicator of your body’s need for fluids, and that there is a window of time over which you can rehydrate safely.”

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"People think it must be fun to be a super genius, but they don't realize how hard it is to put up with all the idiots in the world."

 
Huh?

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Dr. Philip Skiba
Scientific Training for Endurance Athletes now available on Amazon!

If I'm remember right, both those studies where done with fluid loading at rest, not exactly a real world test.

There are fairly consistent observational studies from IM and marathon events demonstrating that weight LOSS is associated with no hyponatremia and faster finishing times.

As I said, read the papers and follow the paper trail. For instance:

Br J Sports Med. 2006 Mar;40(3):255-9.

There are others which are also "real world".

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Dr. Philip Skiba
Scientific Training for Endurance Athletes now available on Amazon!

"Huh?"

with respect, a lot of folks in science would say it is you who needs to, "follow the paper trail." yes, noakes has written reams about this. he's also been the most successful evangelist in this area, which is pretty remarkable when one considers that the big money is with the manufacturers (e.g., gatorade) who're more consistently standing on the other side. my point is, for all the noakesians there are at least as many, most probably more, anti-noakesians. we just had a thread about this within the past week.

i don't have a dog in this. i'll go where the science leads. i'm interested in seeing how you characterize the anti-noakesians. or would it be anti-noakesists?

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Dan Empfield
aka Slowman

Dan,
Sounds like time for another ST investigation topic. You did a wonderful job on Global Warming, wonder what you could dig up on this one?

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Just Triing
Triathlete since 9:56:39 AM EST Aug 20, 2006.
Be kind English is my 2nd language. My primary language is Dave it's a unique evolution of English.

Well,

on the flip side: What about the aspect of conditioning your body to retain fluids more efficiently?

Fact is: Some people tolerate dehydration much better than others.... and get more easily "overhydrated".

So, it certainly makes sense to look into that.

Training while constantly slightly dehydrated could actually improve the bodies resistance to dehydration?

Blasphemy!


"Drink responsibly"

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___________________________________________
Ego numquam pronuncio mendacium,
sed sum homo salvaticus

"Sounds like time for another ST investigation topic."

i thought the very same thing. hence my post on pz pearce (whom i do not know). as it happens i've formed friendships with some of the folks who're front and center on this issue. it's remarkable to me that something this basic an elementary is in such play: am i supposed to drink before i'm thirsty? after i'm thirsty? is that really thirsty, or just kinda thirsty? and should i take 20 salt tablets during my IM, or no electrolytes at all, or something in the middle?

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Dan Empfield
aka Slowman

Well, I think there are a couple of things that bear mentioning...

Noakes is an evangelist, to be sure, and I think he often overstates his case and perhaps evangelizes to the detriment of his cause. I do not necessarily see a great conspiracy of manufacturers to misinform. Nor do I think the ACSM made up it's hydration guidelines (which are changing to be more "Noakesist", as I understand it) based on influence from the supplement industry. All that said...

I disagree with your assertion that there are as many "Non-Noakesians" at this point as there are "Noakesians". Even in the purely clinical setting (which usually lags the research world by a fair measure), there were nephrologists saying the same sorts of things before Noakes really got any steam behind him. At the end of the day, exercise induced hyponatremia fulfills the major diagnostic criteria of SIADH, the primary treatment of which is water restriction. Is it possible to have hyponatremia in the settings of euvolemia, hypovolemia, and hypervolemia, yes. However, the euvolemic and hypovolemic varieties are not typically seen in the endurance sports arena. Some of us were talking this over at the latest ACSM meeting...none of us could recall a case of hyponatremia in an endurance athlete that was anything other than hypervolemic.

I can't say too much about the "Non-Noakesians" at this point, simply because their viewpoint is not well represented in the literature. I can say that most of the sports physicians I have worked with who were "Non-Noakesians" were of that ilk because they were unaware of recent publications, and because they live and die by documents such as the ACSM's guidelines, rather than the primary literature.

Is it as simple as voluntary "overdrinking"? Maybe, maybe not, at least not in all cases. People with SIADH are driven to drink, and I do not think such a phenomena is outside the realm of possibility in endurance athletes. However, as far as I know no one has demonstrated such a drive in endurance athletes, or formally investigated the motivation of the athletes to drink quite so much. I suspect it might go beyond that they got poor hydration advice ("drink as much as you can".) I can say that in the cases where I have played a major role in treatment (around a dozen, all told, some worse than others), I have only heard variations of one explanation. "I was feeling bad, and I thought I must be dehydrated, so I drank more." All patients had had a significant weight gain, which can mean only one thing: a positive fluid balance.

Are there other viewpoints, sure. However, the people who believe hyponatremia is due to electrolyte loss don't have much data to stand on. The people who believe it can be corrected through the administration of oral electrolyte preparations are lacking data as well.

At this point, I think it is pretty hard to argue with the overdrinking argument. I think there is more to be learned about the actual mechanism, but at the end of the day, the treatment may well be the same.

Phil

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Dr. Philip Skiba
Scientific Training for Endurance Athletes now available on Amazon!

"I can't say too much about the "Non-Noakesians" at this point, simply because their viewpoint is not well represented in the literature."

that's interesting. i wonder whether andy coggan, or bob murray, would agree with this statement. and, it guess it depends on what among noakes' views you consider officially noakesian, his views on over-hydration, or what i take to be his views on whether and how much electrolyte replacement matters during an endurance event?

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Dan Empfield
aka Slowman

I'm not sure what the definition of Noakesian is, but athletes don't get hyponatremic if they don't gain weight - this is a robust finding from multiple studies. Weight gain is from overhydration, independent of salt intake. A long distance athlete who maintained a perfect volume status would actually lose weight, through aerobic metabolism of carbs/fat. The common denominator in hyponatremia is weight gain. You don't gain weight by losing salt. You gain weight by drinking.

Based on personal experience, I agree with this. I'm the only one in my 45-minute spin class without a water bottle. Don't need one. When I did my first two marathons and first triathlon, I followed the conventional wisdom and drank a lot and was sick as a dog. When I do sprint tris now, I get by with a sip of water in T1 and T2. Anything more and I get nauseous. My daughter is the same way. Must of had some camel beastiality going on with my ancestors.
BTW, when I see people walking around downtown Chicago with their water bottles it reminds me of babies with their pacifiers.

 

Can't say Andy and I have ever discussed hyponatremia / electrolytes. In any case, you need only go to Pubmed and start poking around. It has been several months since I have done a really thorough literature search on the subject, but as of my last major library dive, there wasn't much out there on the electrolyte-supplementation-as-prophylaxis issue....and what was out there leaned more towards the "not mattering" end of things. There are sports docs out there who have their football players drinking pickle juice and whatnot, but the real question is how much of what passes between the lips ends up in the plasma, and even if it does, does it matter? That has been a hard case to make, so far.

There was a study (again, by noakes et al, IIRC) where they showed that the link between electrolyte imbalances and cramping was somewhat weak. Now, I have anecdotal reports from my patients who claim their cramping issues magically disapeared after taking endurolytes or something....and really, who am I to argue with them? It worked for them, they are happy, fantastic. But in the bigger picture, we need to be more evidence based than that. At least, I feel like I need to be.

Regarding the hypervolemia thing, I can't find much to criticize there. That work is quite well replicated...gaining weight = lower sodium. If you have a line on some good data that says otherwise, I'd be interested in it.

Phil

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Dr. Philip Skiba
Scientific Training for Endurance Athletes now available on Amazon!

When I do sprint tris now, I get by with a sip of water in T1 and T2. Anything more and I get nauseous. My daughter is the same way. Must of had some camel beastiality going on with my ancestors.
BTW, when I see people walking around downtown Chicago with their water bottles it reminds me of babies with their pacifiers.
By best half-IM effort was on about 40-50 oz of water and the last one at World's Toughest Half was about 70 oz for not quite five hours of effort. I always get attacked when I see threads about peeing on the bike and suggest that if they are doing that then they are drinking too much. People ought to experiment with how much they should drink and then get by with the bare minimum for racing. More is not better in this case, but heaven help you if you try and convince anyone of it.
Chad

"There was a study (again, by noakes et al, IIRC) where they showed that the link between electrolyte imbalances and cramping was somewhat weak."

i see to recall from noakes the view that it matters not whether you take electrolyte replacement or clear water, there's not demonstrable benefit to either over the other. if i am representing this correctly as his view, i personally think that's the more eyebrow raising believe than the hypervolemia views he holds.

that said, i'm going to have to be brought along to the view that dehydration is not really anything to much worry about, whereas hyponatremia is the big flashing red danger light. i find this a bit ironic since in 2001 noakes was considering not allowing petr vabrousek to compete in IM south africa (noakes was the race's medical director) because the czech was admitted to the hospital a week before, diagnosed with heatstroke and gastroenteritis. heatstroke is specifically hypovolemic. noakes would tell you that elevated rectal temps are very rarely seen in these long distance athletes. i suspect when noakes shoved a thermometer up petr's ass it registered pretty red.

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Dan Empfield
aka Slowman

1. Electrolytes, or, "salt doesn't matter"
The Boston Marathon article, NEJM 4/14/2005 - fluid consumed (sports drink versus plain water) did not affect rates of hyponatremia.
2001 Capetown IM (a Noakes article), British Journal of Sports Medicine, 2006 - A randomized controlled trial. Athletes were given salt tablets or placebo tablets, and had no difference in sodium concentrations after the race. On average, athlete's took 15 salt tablets during the race, or the equivalent salt content to 9 liters of gatorade.

2. Heat Stroke.
IM Western Australia, British Journal of Sports Medicine, 2006 - 10 competitors swallowed temperature sensing "pills". Core temps increased 1 degree C, in spite of weight loss averaging 2.3kg, or 3%.
2000/2001 Cape Town IM (Noakes again), British Journal of Sports Medicine, 2004 - rectal temps of 700+ athletes. Weight gain or loss (as a surrogate for fluid intake) made no difference in rectal temps. As a group, people who lost 6% of their weight had no difference in rectal temp compared to those who lost only 2%. 6% is 10 pounds for me! More weight loss also trended towards faster times (so it's not as if they were working less and generating less heat).


As far as people (the media, race directors) being nervous nellies, people who die while racing either drop dead from coronary events, get caught in an accident, or drink themselves to death through hyponatremia. You can't prevent coronaries and accidents happen, but hyponatremia is preventable. Dehydration never killed anyone in a race. If you get dehydrated, you bonk, you sit down, rest, drink some water, and start again at a slower pace. If you get hyponatremic, you drink some water, feel worse, drink some more, get confused, your friends have you drink some more, then you seize and die. That's not to ignore that profound dehydration might affect performance, or that heat exhaustion happens; they're just not nearly as dangerous.

Here's the thing...to believe that sodium supplementation is going to significantly impact plasma sodium concentrations (for good or bad), you have to believe that what is passing between your lips is rapidly equilibrating with your blood, which may or may not be true in the setting of exercise. You have to believe that you aren't just creating an osmotic load in the gut that is causing fluid shifts within the body. You also have to believe that you are able to "outsmart" the fairly sophisticated machinery in your body that is attempting to preserve plasma osmolarity. These are all fairly large assumptions, and again data supporting these assumptions is not particularly abundant.

In terms of dehydration, the truth is that while it is not innocuous, it is rarely fatal. I've treated A LOT of people (perhaps a hundred?) with pretty bad dehydration, with or without concurrent heat illness. I have never seen a fatality. However, of the dozen or so people I have seen with hyponatremia, I've seen two fatalities, one of which was extremely gruesome. I'm not going to monday-morning-quarterback another physician's clinical decisions regarding race fitness...we don't know what the clinical presentation was. (I'm not familiar with the case at all). I will say this: saying dehydration is not as big a deal as hyponatremia is not the same as saying, "You were admitted to the hospital for gastroenteritis and heat stroke, you may or may not be 100%, your volume status may not be exactly right just yet, and your gastric/intestinal mucosa may not be 100% healed, go ahead and participate in an extremely strenuous athletic event that will specifically stress all of those systems." Smart money says you keep the athlete out to race another day.

Phil

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Dr. Philip Skiba
Scientific Training for Endurance Athletes now available on Amazon!

"fluid consumed (sports drink versus plain water) did not affect rates of hyponatremia."

perhaps i misunderstand noakes' view. i'm parsing the issues of safety and performance. let us concede that salt intake does not affect rates of hyponatremia. my further understanding was that noakes did not believe levels of salt intake affected performance. that was that eyebrow raiser for me, but maybe i'm ascribing to noakes a view he does not have.

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Dan Empfield
aka Slowman

Indeed, it is quite remarkable, especially when you consider that Noakes hasn't conducted a single experimental study to support his claims. OTOH, there are literally tons of data out there showing that performance is negatively affected when one becomes dehydrated by as little as 1-2%, as well as data indicated that replacing 100% of the fluid lost during exercise results in best maintenance of sweat rate, heart rate, stroke volume, etc.

Or to put it another way: you have to do more than just skim through a few papers and/or chat with a few graduate students to understand the real story here...you have to dig into the data, and base your conclusions on what it actually shows (vs. what a self-described iconoclast such as Noakes claims it shows).

Precisely - and you seem to be confusing or at least confounding the issue by lumping all of Noakes' ideas together. That is, while you'll find plenty of people who agree with his observation that hyponatremia can occur during prolonged exercise due to overhydration with fluids containing no/not enough sodium, you'll find very few that will agree with his conclusion that the solution is to just let yourself become dehydrated.

okay, now we have the entire varsity here. finally. (andy, were you under the bleachers cavorting with cheerleaders again during the coin toss?)

what we appear to have are several reasonable, highly educated, folks participating on this thread, and there seems to be some difference of opinion on the literature. in truth, i've seen a lot of literature on both sides. yes, andy is right, there is certainly a plethora of literature that states the ill effects of dehydration.

i guess i have two questions, i'm happy to have anyone answer, and my questions are pursuant to a framing of the issues and the nature of the literature.

first, it seems to me that a lot of noakes' writings are born of the work he's done at races, that is, he performs his "study" at ironman south africa, or comrades, or some sort of ultra ultra distance triathlon. is this what you mean, andy, when you say he hasn't conducted a single experimental study, that the studies about which noakes writes are often just a grouping of 20, or 200, or 2000, "anecdotes" collected an athletic event? does this explain the difference in the views expressed on this thread regarding "literature," that noakes' "literature" consists of these sorts of "field tests," plus his manifestos on hydration protocols, and these are not considered in the same class as that which would be conducted in a lab setting?

second, i wonder if we might parse between performance and medical danger. when we're talking about dehydration, are people talking past each other because noakes' interest is in who lives and who dies, versus the consequences of dehydration or salt intake on performance? in other words, how fair or unfair would it be to characterize noakes' view as: "follow my hydration protocol and you may go slower, but you're also more likely to survive the race with your life."?

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Dan Empfield
aka Slowman

A few thoughts:

In my experience thirst is not reliable. I lost 12 pounds at IMFL last year without feeling thirsty. Probably slowed due to this in second half of marathon, but my time wasn't far off my potential.

Though the body has mechanisms to regulate sodium balance, they fail miserably in those who suffer catastrophic hyponatremia. SIADH is the obvious culprit.

So what can be done to protect athletes when thirst and the body's homeostatic symptoms aren't fool proof? The answer is availability of scales at aid stations, IMO. They may not be perfectly accurate, but we're trying to prevent catastrophic weight gain on the order of 10 or more pounds.

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Coach at KonaCoach Multisport

True, and I would not say that the best strategy is to simply allow yourself to dehydrate. However, we should be careful to differentiate between *performance capacity* and *welfare of the athlete*. Most athletes are not going to the trouble of figuring out how to properly hydrate, or even properly prepare for a marathon or IM. Thus, the *safest* advice might be to drink to thirst. Coming to the finish line dehydrated by a percent or two at a slower pace, or even a DNF, is better than the alternative.

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Dr. Philip Skiba
Scientific Training for Endurance Athletes now available on Amazon!

 

It's funny...you wrote this just as I wrote the same thing in response to Andy's comment. I think this "parsing" is particularly important in our sound-bite, "do an IM or marathon on little training for the experience" culture. You aren't going to get your message out to the lay public if you get into the complexities of hydration, electrolytes, etc. Noakes has been successful in getting a very basic, fairly reasonable message into the media which any amateur athlete can remember: "don't overdrink".

Phil

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Dr. Philip Skiba
Scientific Training for Endurance Athletes now available on Amazon!

I don't think I would characterize them as anecdotal...he does check labs, he does weigh the athletes, etc. However, such studies are not necessarily at the level of a highly controlled, laboratory investigations. I very much agree with his observations regarding weight gain, overdrinking, and hyponatremia. However, as Andy pointed out, this observation does not support his contention that dehydration is the best strategy.

Regarding the electrolyte issue, I'm not aware of any studies that have indicated that electrolyte supplementation improved performance, or significantly impacted plasma electrolyte concentrations during exercise. (Most studies I am aware of that showed performance benefit included carbohydrates in the replacement beverage, and I would argue this is where the benefit came from.) This does not mean electrolyte supplementation is unimportant, only that I am unaware of data on that point. Andy, do you know of anything off the top of your head? Pubmed came up dry for me.

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Dr. Philip Skiba
Scientific Training for Endurance Athletes now available on Amazon!

Essentially, although I wouldn't use quote around the word study, as the approach he's used is certainly a very valid means of describing what actually happens at such competitions. When it comes to why it happens, though, you really need to do controlled experiments, which are most readily conducted in the laboratory, not in the field.


No, the difference stems from the fact that Noakes is, to be blunt, someone who would apparently be just as happy being known as being right. That is, IMO he is overly willing to ignore data that contradicts his unusual points-of-view (plural, because this is but one of many issues on which Noakes has adopted a position that is contrary to the evidence...as I mentioned before, he himself says that he's an iconoclast).


No, I think that Noakes is a true believer in his own religon, i.e., he's not tailoring his message to try to achieve some altruistic goal.

Ron Maughan was at that same UK Sport meeting that I attended earlier this year, and IIRC he discussed a study showing less of a decline in plasma sodium in subjects consuming a salt-containing sports drinks than subjects who drank only water. Beyond that, though, the details escape me.

"I always get attacked when I see threads about peeing on the bike and suggest that if they are doing that then they are drinking too much."
- - Absolutely agree. Under strenuous exercise, the kidneys will shut down, at least partially, preserving fluid volume because so much is lost through sweat. I think the problem is caused by people hydrating excessively prior to racing.
I've found that if I take in a lot of fluids in the pre-race hours, I'll be feeling the need for a pit stop before the race is over. I've also found that (for me) if I drink 10-16 oz. of (used to be whatever I was racing with, but this year it's Infinit's pre-hydration formula) just a few minutes before entering the water, then I don't feel thirsty and can start taking in my drink mix on the bike to hold off that thirst without feeling any urge to empty my bladder. In fact, I usually don't even head for the head after the finish line until I've downed a few liters of fluids and have been just wandering around for a half hour or more.

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

Slowman, after a near death overhydration 20 lbs weight gain (10 from my own stupidity...10 more in the medical tent stupidity....) at IMLP 2003, I had a fair amount of discussion with Noakes on this topic. While others can sit with their lab coats on with a smug look on their faces from their "highly accurate" white tower academic papers, I'll go with the field studies from Comrades, Ironman South Africa and Ironman New Zealand that Noakes has conducted.

I followed the usual hydration to death routines that were generally prescribed and never figured out why I felt like crap for my first 10 Ironmans....then after talking to Noakes, I realized that I could actually do a hot Ironman like Kona on 4 bottles of Gatorade on the bike and some cups of gatorade and coke on the run still post a PB!

My family comes from a part of the world where it is 95% humidity and almost 100 degree heat 10 months a year. There, you cannot leave salt in salt shakers....it turns to slush in a day. You have to add grains of rice to keep the salt from liquifying from absorbtion of humidity from the atmosphere. Not sure if it is genetic, but everyone in my family have really low sweat rates. Must be an evolution thing for surviving in such a climate....I don't know....

Regardless, it is really important for people to find out their real sweat rate. Head out for a 90 min run and replenish with zero water in a variety of temps and do before and after weigh ins to find out what you really need to replenish. Under replenishment will not kill you.

Like you said, yes performance might drop marginally and Dr. Coggen points out due to mild dehydration, but it is extremely rare that fit athlete will die from dehydration. The likely outcome is that the athlete slows down a bit as a form of self preservation. However, we as a species only drank water when we needed it, using thirst as an indicator. Overhydration is not really a part of human evolution. Man did not drink when he was not thirsty. Death from hyponatremia is very real.

I've spent 4 years recouperating from the post concussion symtoms resulting from the intracellular fluid putting pressure on my entire brain encased in a physically fixed volume skull. I'm lucky that I did not die from a herniated brain stem. I'm also lucky to not have died from central pontine mylenolysis from rapid correction of sodium levels after this all occured. I did have nerve damage and lots of short term memory issues, nausea and deterioration of fine motor skills for a long time that have finally largely cleared up, although I go through a day or two a month when it is still an issue.

Please people, find out what you really need to drink. An aid station every mile in most marathons or Ironmans, especially for slower finishers who actually can take in entire cups of liquid (hard to do for 7 min mile runners....) is largely overkill. A bottle every 10 miles on the bike is likely too much for most people...but people take all this in cause the aid stations are there. Noakes found in his "real world tests" that if they reduced the number of aid stations, they actually ended up with less athletes in the medical tent. In fact, and my memory may not seve me perfectly, in one year at Ironman New Zealand, they treated zero athletes with IV's despite less aid stations than IMNA events.

Peace...be safe....those aid stations could actually kill you....but as a bare minimum, they may be taking away from your race day performance...

Dev

Edit: Last year at Ironman Hawaii, I weighed in race morning at 140 and ended the race at 138, on 4 bottles of Gatorade on the bike, and whatever I had off the course every other mile on the run. Please keep in mind that my Wed weigh in was 138 too. The final 2 lbs of weight that I gained was from all the water you retain when you carb up. Conversly, when I gained the 10 lbs in a 50 degree rain storm at IMLP 2003, I drank in the order of 8 bottles on the bike and then on the run, was drinking a coke and gatorade EVERY aid station. Then I slowed to a walk and was drinking chicken broth....way too much for my body!!!

I think the problem is caused by people hydrating excessively prior to racing.

Agree. And not just the day of, but in the days leading up to race day. I wonder also if this contributes to hyponatremia, i.e. coming to the start line relatively hyperhydrated and depleted of sodium. Does anyone know if this has been considered/studied in those who have developed hyponatremia?

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Coach at KonaCoach Multisport

You might mock me as "someone who sits in their lab coat with a smug look on their face", but at least I've never drank so much that I actually gained weight while training or racing. ;-)

Fair enough...I was just following the cookie cutter hydration recommendation of the lab coat crew...now I go with what Noakes recommends and I'm faster at 41 then I was when I was 25!

Indeed, it is quite remarkable, especially when you consider that Noakes hasn't conducted a single experimental study to support his claims. OTOH, there are literally tons of data out there showing that performance is negatively affected when one becomes dehydrated by as little as 1-2%, as well as data indicated that replacing 100% of the fluid lost during exercise results in best maintenance of sweat rate, heart rate, stroke volume, etc.[/reply]The above quote from dkv personally scares me:
"As a group, people who lost 6% of their weight had no difference in rectal temp compared to those who lost only 2%. 6% is 10 pounds for me! More weight loss also trended towards faster times (so it's not as if they were working less and generating less heat)."

6% loss?!?!?!? At ~160lb that would be about 150.4lb for me. If I've been out running for a long time and not keeping track of water I can easily lose 2-3lb. But at 155lb I stop sweating almost entirely and am forced to walk. This has only happened two or three times over the last 5 years, but I can't even IMAGINE losing nearly 10lb. Something is seriously wrong with the above study, as it totally contradicts everything I've ever read, and what Andy just said above. I can understand body temperature not being substantially different, as the people who are better hydrated are performing better and their bodies are generating more heat, etc. But the above study seems to say the opposite, which makes little to no sense.

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Dev, I'm the Yin to your Yang, or maybe I'm the Yang, but whatever. My people come from a long line of extremely pale, heat averse people. I need about 40oz of fluid per hour when the temps creep over 85 or so.

Strange. So if I'm pissing completely clear, but my throat is dry as nails and I'm thirsty - then I'm dehydrated? Maybe some would debate what the term "thirsty" really means.

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- - - - - - - - - - - - - - - - - - -

Not if you gained 10 lbs, you weren't.

I think it's fair to say that hydrating like mad without having a clue of your normal sweat rate is borderline suicidal. :) I did this experiment myself on the bike a few years back by riding at race pace for 30 or so miles and drinking a known volume of water. Weighed before and after and found my sweat rate in the Floriduh sauna to be in the range of 1.9L/hr (which is on the high side of normal IIRC). This has driven my hydration plan for hot and humid days. My sweat rate on cooler days is dramatically less, so I have to pay attention to how much I am sweating. After 3 years of religiously checking pre and post workout weight I know have a pretty good handle on my hydration level and can usually maintain it within 2lb of "normal."

Here's a followup question on salt and hydration for the experts. I typically sweat a lot as mentioned above. In order to take in enough water I usually take a Thermotab (450mg NACl) or Saltstick cap (550mg NaCl) about every 45 minutes and this seems to help a lot with gastric emptying, especially on the run where I can go from a sloshing stomach to normal in about 5 minutes. If I take in the same amount of water without the salt it tends to just sit in my stomach and I get bloated. Is there any literature to actually support my n=1 observations?

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The cookie cutter hydration recommendations floating around do not take my low sweat rate into account.

Andrew, you are a smart guy, but unless you were there, in the situation on that day in 2003, don't pretend to know more about the situation on the limited information you have read to this point. Noakes is not the only one that I spoke with after that day. I consulted with numerous medical professionals, specializing in everything from kidney to brain function, who I'd argue have a better grip on this topic than most self professed "ST experts of all domains".

Dev

i suspect when noakes shoved a thermometer up petr's ass it registered pretty red.

The thermometer or the ass?

well, i think we've figured out what not to do: gain 10lb during a race, or lose 10lb during a race. i also am quite happy to have various sports doctors liaise with race promoters in order to find a consensus as to how many aid stations ought to be on the course, and how to treat distressed athletes post-race.

all this leaves us with the most important question for those on this forum: how to recognize the symptoms of hypervolemia or hyponatremia during the event itself, and to hydrate properly (instead of simply erring on the side of underhydration). for all practical purposes, i'm still finding myself thinking, when i parse the statements by the noakesians, that they're looking at this strictly as a safety issue. me, i'm also interested in performance. i mean, using this same reasoning, here's my protocol for bike safety: go slower on descents. your performance may suffer, but you're more likely to live or escape serious injury.

i'm hoping that the noakesians can provide the end users with a hydration protocol that is both performance and safety specific.

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Dan Empfield
aka Slowman

And what "cookie cutter" recommendations were those?


You don't have to be very smart to understand that drinking so much that you actually gain weight while racing is a pretty dumb thing to do...

all this leaves us with the most important question for those on this forum: how to recognize the symptoms of hypervolemia or hyponatremia during the event itself

Weight is the only reliable and practical way to assess on-course hydration status. Bathroom scales aren't expensive.

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Coach at KonaCoach Multisport

You don't have to be very smart to understand that drinking so much that you actually gain weight while racing is a pretty dumb thing to do...


You don't even have to think at all -- just follow some of the articles that "coaches" have written where they recommend taking in a ga-jillion (that's a scientific term) calories during a race. Then people wonder why they had "stomach issues" during the race. Hey, I know... You need to try "BrandX" instead! It's got Mega-SuperLow Osmality vectors!

You don't have to be very smart to understand that drinking so much that you actually gain weight while racing is a pretty dumb thing to do...

Unfortunately, the ADH system doesn't know smart from stupid.

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Coach at KonaCoach Multisport

"Weight is the only reliable and practical way to assess on-course hydration status. Bathroom scales aren't expensive."

this takes us back to 1981. ironically, the only thing that mattered to the IM organizers back then was whether i was going to lose 10% of my body weight. so they weighed us 5 times during the event. in point of fact, they ought to have been worried about my gaining weight, eh? i started that race at 161 lb, and got up to 163lb during the race, eventually finishing it at 158lb.

i rather think there may be other things that are harbingers of weight gain, such as circumferences. is your ring, or your watch, fitting tight, with your skin bulging out around it/them? what about skin texture and color? come on! is weight gain it? let's face the reality that we're not going to have a line of people waiting to stand on the scales at the weigh stations, like a caravan of tractor trailers on the interstate. let's have the experts "weight in" on the other signs of hypervolemia an athlete can recognize during an event.

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Dan Empfield
aka Slowman

Do IMNA events have scales on the course or only at the end ? I'm doing my first this august and it's going to be hot so I'd like to figure this one out.

Dan
http://www.aiatriathlon.com

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http://www.aiatriathlon.com

I think Devashish Paul put it right when he wrote, "Please people, find out what you really need to drink." People need to know what their sweat rate is at race pace and calculate how much they need to drink to stay slightly negative in the weight department.

As far performance goes, there's a lot of real-world observational data that faster marathoners and triathletes lose weight. It's the MOP/BOPers who gain a lot of weight and get the most hyponatremia. I did a lot of searching for published data on dehydration negatively affecting performance, and found one paper. It was lab-based, and compared maximal intensity cycling for 5 or 10 minutes (can't remember which) and showed a difference in maximal power output. This kind of anaerobic power output should be irrelevant to the readers of this forum.

I don't fault triguy42 for thinking that 6% weight loss is crazy, but people have done it without adverse effects on their performance or thermoregulation. To paraphrase Devashish Paul,every person is different. Do what works for you. That being said, I wouldn't be afraid to lose significant weight during competition as long as I felt good. I would be afraid if I gained as little as half a pound.

There are far more papers than that.

The issue of weight loss and fluid status during endurance exercise is complicated by the metabolism of fuels burned.
Carbs and fat combined with oxygen = heat, carbon dioxide, and water.
Carbs are also dissolved in water in the body. This water associated with glycogen is released as the glycogen is burned.
Burning fuels will result in weight loss without changing fluid status, as carbon dioxide is breathed off. This sounds crazy but it can add up over the course of an IronDay to something substantial. So you lose weight just from exercising for so long, so if you lost a bit of weight during the day you would be fluid status neutral. Add in the water liberated by the metabolism and it's like drinking a liter or two of water, so you could be down a couple of kilos without becoming fluid negative.
I'll post a reference if anyone wants.

I bring a scale with me to transition. I leave it next to my bike on races where you rack it yourself, and put it in my transition bag otherwise. Step on it, make sure weight isn't either high or excessively low, off I go. This saved me on on IM race where I was 4lb down off the bike and was getting fatigued/crampy in the last 10-15 miles before T2. I took the first few miles slow and rehydrated. I finished at about 2-3lb down from original weight, which is not bad considering I burned off 10,000 calories (3lb of fat).

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Clue me in. I'll read 'em.

you can't do that at IMNA can you? Is there a scale in the change tent?

Dan
http://www.aiatriathlon.com

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http://www.aiatriathlon.com

i rather think there may be other things that are harbingers of weight gain, such as circumferences. is your ring, or your watch, fitting tight, with your skin bulging out around it/them? what about skin texture and color? come on! is weight gain it? let's face the reality that we're not going to have a line of people waiting to stand on the scales at the weigh stations, like a caravan of tractor trailers on the interstate. let's have the experts "weight in" on the other signs of hypervolemia an athlete can recognize during an event.

Sorry my MD credentails aren't sufficient for you. When I attended a CME conference with the "experts" on this subject prior to Boston marathon last year, I learned "Drink when you're thirsty." Wow, that's all they could come up with?!?

As for the waiting issue, if they can have 2000 participants use on course porta-potties without a bunch of waiting in line, I feel sure they could find an efficient way to allow participants to voluntarily weigh themselves without undue waiting. Probably only 10% of the field would even choose to do so.

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Coach at KonaCoach Multisport

"So if I'm pissing completely clear, but my throat is dry as nails and I'm thirsty - then I'm dehydrated?"
- - Not sure if that's possible, but I suppose it could be. I wouldn't say that urine color or even concentration (electrolytes, vitamins - which are more likely to cause coloration - or what have you) is necessarily related to dehydration because of the time lag factor. What's coming out went in hours ago. As I stated in another post above, your kidneys shut down (at least in part) in response to strenuous exercise, when your body needs to conserve and preserve fluids.
On the flip side, if your throat is as "dry as nails," I'd say you're behind the curve on rehydration. Whether this will affect performance is a matter for some discussion as you've no doubt read above. My own experience (n=20, because I've had a number of my athletes report the same) is that you can get behind the curve during the swim, especially at long course races. Hydrating in advance (by a few minutes) can help with this, while hydrading WELL in advance (an hour or more) seems to be counterproductive as it fills the bladder and depending on your choice of fluids can potentially dilute your electrolytes, possibly causing some loss of same through the kidneys.

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

Andrew, I do agree that gaining or losing 10 lbs in a race is a dumb thing to do. I'm not removing personal accountability here, but athletes don't end up doing type of shit intentionally. Most don't even recognize the symptoms in hyponatremia (hpyo or hypervolemic) when they start kicking in. To compound the problem, when an athlete gets to this point the brain function is already impaired, so yes, at this point one might be getting dumber than at rest. Part of doing well in a race is being smart and making smart decisions. That is just part of racing. Slowman would like to now understand the protocol for hydration that would result in good performances, while remaining safe, so that we can all make smart decisions in racing.

Frankly, I believe I have found my sweet spot after discussion with Noakes and it would border on the extreme end of "under hydration" if you looked at it simply by the absolute quantity of fluids consumed.


I'm not going to comment on which cookie cutter approach I used previously, but I do not fall anywhere close to anything that any of the rules of thumb coming out of the so called labs going back to 1990 would suggest. But obviously now that you make this statement, you contradicted your previous one, for without knowing which cookie cutter approach the athlete was following you cannot say if he was following it or not.
Dev: I was just following the cookie cutter hydration recommendation of the lab coat crew[/reply]Andrew: Not if you gained 10 lbs, you weren't.

Andrew: Not if you gained 10 lbs, you weren't.
[/reply]No, I didn't, because no "cookie cutter" hydration recommendation would ever result in your gaining 10 lbs.

Dev, some very interesting stuff in your experience, and some observations that are brilliant.

"20 lbs weight gain (10 from my own stupidity...10 more in the medical tent stupidity....)"
- - Surprisingly much of the "conventional" wisdom (by the athletes and also by the non-experts who staff these races) is that more is definitely better and too much is just enough. Many of us who study sports performance, whether formally or anecdotally or both, are aware that overhydration has it's dangers as well, but most race volunteers and certainly the majority of competitors are woefully underinformed (I shun the term "ignorant") on the parameters, especially one that you noted, ethnicity/climate of origin.

"after talking to Noakes, I realized that I could actually do a hot Ironman like Kona on 4 bottles of Gatorade on the bike and some cups of gatorade and coke on the run still post a PB!"
- - Which makes you rara avis, but then we knew that already!!

"My family comes from a part of the world where it is 95% humidity and almost 100 degree heat 10 months a year... Not sure if it is genetic, but everyone in my family have really low sweat rates. Must be an evolution thing for surviving in such a climate"
- - Give that man a cigar!! You've hit on something sorely underreported and understudied. I can't say that it's necessarily genetic, but it well could be. I've discovered that a great many health issues can be ameliorated by eating the foods that are culturally consistent (what your ancestors ate which is usually dictated by the region and climate in which they lived). As to sweat rates, I know that those can vary depending on the climate where you live, but might well be affected by the climate where your ancestors lived.
My own experience showed this dramatically. I grew up in CA (moderate climate both in temp and humidity) and always had a more or less "normal" sweat rate. After living in Baltimore (stinking hot, although not quite as hot as your parent's land of origin but certainly as humid, reaching +95% in August) and Chicago, my sweat rate increased dramatically. So much so that it was/is totally unecessary (despite anything Dr Coggan may interject) for any sort of testing to verify this. Even while exercising back CA, where I've now lived in the more moderate climate for the past twenty-two years, I still soak through a t-shirt during a hard workout in a very short time.
While living in Chicago, I went to Tucson, AZ (It don't git no drier than that in North America) and came close to suffering heat stroke from dehydration during a mid-morning training run. The heat and dryness pulled the moisture off me at such a rate that I didn't realize I was in trouble until I stopped for water after about 90 minutes (running in a unknown area and not finding water along my route, because I'd have normally taken some water in that much time) I must have drank a gallon without slaking my thirst in the least bit. I ended up walking back and experiencing severe symptoms such as dizziness, confusion, etc.
So what I find interesting is that (thinking out loud, no science here just guesswork) you coming from a line of ancestry accustomed to extremes of heat and humidity might be well prepared genetically or evolutionarily to withstand heat so that your sweat rate under any given conditions could be less than half of what mine is and even lower than mine was prior to living in hotter climates. This would certainly make sense from a logical perspective, although that's totally unscientific. So the temps and humidity in Lake Placid were far less than you were equipped to handle, where the higher-than-CA heat and humidity there would be likely to send me into a flop sweat the minute I got off the plane!!

"Regardless, it is really important for people to find out their real sweat rate."
- - Amen to that!!

"Like you said, yes performance might drop marginally and Dr. Coggen points out due to mild dehydration, but it is extremely rare that fit athlete will die from dehydration."
- - Dehydration might be the lesser of two evils, but having experienced it, I wouldn't recommend it! So definitel, *** FIND YOUR SWEAT RATE ***

"However, we as a species only drank water when we needed it, using thirst as an indicator. Overhydration is not really a part of human evolution. Man did not drink when he was not thirsty."
- - Another brilliant observation. Listening to our bodies is the way to go.

"An aid station every mile in most marathons or Ironmans, especially for slower finishers who actually can take in entire cups of liquid (hard to do for 7 min mile runners....) is largely overkill."
- - Right on once again. I can recall running marathons in thirty years ago where aid stations were five miles apart and only had water. I'm pretty sure my performances weren't impacted in any negative way.

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

I did at IMFL, just stuck it in my T2 bag. One guy next to me at the change building asked to borrow it too. I bet he brings one next time!

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OK, this getting brilliant...first time ever on ST that we have stooped to the depths of arguing about which cookie cutter protocol results in which weight gain outcome.....I can't wait to see the study on this one,....A study to end all studies.

Abstract: "The paper describes as cookie cutter protocol under which the average athlete gains no weight over an Iron Distacne event. The paper presents the hydratoin and performance outcome of 2000 moderately trained endurance athlete in an open loop environment, where the weather, pre race diet, in race diet, body fat, blood sodium depletion rate, genetic kidney function of all participants, and susceptability to SIADH is unknown, under weather conditions ranging from 278 to 288 degrees Kelvin and 70% humidity in a Noah's ark style North East Monsoon Deluge. The impact of the use of short sleeve vs long sleeve wetsuits and the initial dramatic dehydration caused by swimming in 80 degree water for over an hour was never analysed as a possible cause for hyothalmus malfunction and early onset of SIADH. The study found that the average Caucasian participant gained zero pounds, however there were outliers in the group who gained as much as 10 pounds. The statistical significance of the outlier group accounting for only 0.05% of the sample size suggested that the outliers fall into the uncertainty ranges typical of such a study"

I'm still in Chicago (maybe we raced against each other) and sweat profusely when exercising, yet I don't feel the need for any water until I've exercised for about any hour, then it is a sip or two. My daughter who also does tris is the same way (except she does not sweat as much as her old man). More than a sip of water while exercising and we get nauseous. So maybe sweat rate is not the key factor.
I have no scientific or medical advice to offer but, based on my experience, I don't think there is a "one size fits all" hydration method.

"Probably only 10% of the field would even choose to do so."

hey, i'm not trying to diminish anyone's credentials. i'm asking for a sensible, self-diagnosing protocol that works in situ -- during the race itself. you're saying it's just weight. you weigh yourself, during the race. that's the protocol. but as you note, probably 10% of the field would avail themselves of this. i rather think it's closer to 1% than 10%. so, unless you're going to go back to 1981 and make weighing in mandatory, i don't think it's abusive for me to ask whether there's a more expansive protocol.

i note that symptoms of hyponatremia are cramping, nausea, vomiting, bloating, swelling and tightness of the hands and feet, dizziness, headache, confusion, diminished reflexes. i also wonder whether very low-salt diets leading up to the race, the taking of diuretics prior to the race, being on diuretic medications, are also elements that accrue toward a propensity for hyponatremia during the race.

accordingly, i would think there is a reasonable protocol that would aid the athlete in achieving both optimization of effort and a guarding against hyponatremia. perhaps it starts with what not to do prior to the race (take diuretics? overhydrate?), and what to do pre-race (electrolyte load?). then there's your fueling plan during the race, and finally there are the warning signs of hyponatremia. cannot bloating, or skin color or pallor, or skin tension, or excessive tightness of one's shoes, i don't know... are you saying that these have been discounted by the medical community as user-helpful tools for during-race detection of hyponatremia? and, then, what do you do if you think you're potentially going hyponatremic during an event? do you quit the race? do you quit drinking? do you eat some salt tablets? is that last thing useful before some sort of cascading event makes salt intake no longer efficacious?

i don't mean to disrespect to you and the other MDs, i'm searching for end-user tools (beyond searching for a scale to stand on).

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Dan Empfield
aka Slowman

 

In the field, one of the first things we do is attempt to slip a finger under the race wristband or watch. If the person is with it, you ask him if the watch/wristband seems tighter than before the race. You can also look at wedding rings, etc. (And of course, you throw them on the scale, and check their labs. But we are talking about things the athlete can manage).


Personally, I'd recommend bagging the race, and quitting drinking, and seeing the doctor, and *specifically asking them* about hyponatremia. If they don't know about it, ask to see another doctor. I have seen physicians try to provide IV hydration to people who were clearly fluid overloaded.

In most cases of hyponatremia, the treatment is fluid restriction. In really bad cases, we send them to the ICU on 3% saline IV.

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Dr. Philip Skiba
Scientific Training for Endurance Athletes now available on Amazon!

Dan, prior to 2003, in Ironmans when I used the "cookie cutter" hydration recommendations, I would lose "definition in my forearms...I never realized what was going on. As I retained water, the intra cellular fluid would go up. Now if I start getting hypervolemic I can see it when I am in my aerobars in my forearms. It has happened a few times in training since, (never in racing because I am on top of it...) when I got really dehydrated early in the workout (due to lack of easily available liquid) and then at a stop, when I pound back liquid, it just stays in by body (SIADH) because the kidneys are trying to protect me from dehydration by conserving the liquid in my body. Usually after I stop the workout, I then have to pee a lot for the next 4-5 hours when this happens.

I've watched athletes blow up at Kona on TV and when they blow (like Macca a few times in the past), they have no definition in their muscles that they normally would...by then, they are retaining liquid. If you are a lean athlete, loss of definintion will tip you off quickly, but as you said, this itself can be somewhat late.

Dev

I have seen physicians try to provide IV hydration to people who were clearly fluid overloaded.

Yup, I was the victim at the other end of this!

Pretty hardcore Dev sounds like you where very lucky to walk away from that one. Why would the med tent load you up with a IV if you had actually gained weight?

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---------------------------
http://www.nunnsontherun.com

i'm asking for a sensible, self-diagnosing protocol that works in situ -- during the race itself. you're saying it's just weight.

I'm not sure it exists. If the world's experts tell me to drink when I'm thirsty and I lose 12 lbs. in a race without being thirsty, then something's wrong with those criteria, at least for me. If an objective physician in the medical tent can't tell by looking at someone's skin/body whether someone's hyper- vs. hypo-volemic, then is it reasonable to think that I would be able to accurately make this assessement during the race?

i note that symptoms of hyponatremia are cramping, nausea, vomiting, bloating, swelling and tightness of the hands and feet, dizziness, headache, confusion, diminished reflexes.

Many athletes who are euvolemic experience several of these symptoms during a race, so while they shouldn't be ignored, they're nonspecific and/or unreliable.

I contend that exercise of the duration seen in IM racing throws all kinds of curveballs to the body's homeostatic systems. For instance, I shake uncontrollably for 15 minutes or so within an hour of crossing the finish line. I've been told that the body's temperature regulatory system gets "confused" and thinks your body is cold causing the shivers. I don't shake at all after a half IM.

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Coach at KonaCoach Multisport

"If an objective physician in the medical tent can't tell by looking at someone's skin/body whether someone's hyper- vs. hypo-volemic, then is it reasonable to think that I would be able to accurately make this assessement during the race?"

then should we officially delete from the list of symptoms bloating, swelling and tightness of the hands and feet?

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Dan Empfield
aka Slowman

"i rather think there may be other things that are harbingers of weight gain, such as circumferences. is your ring, or your watch, fitting tight, with your skin bulging out around it/them?"
- - Brilliant!! Not being facetious here at all, very impressed. I'm not sure if circumference of the fingers, wrist, ankles or anything else would be good predictors of hydation related problems, but it certainly sounds like it has possibilities. I'll make a not to check that at Vineman, where it will undoubtedly be hot.

"come on! is weight gain it? let's face the reality that we're not going to have a line of people waiting to stand on the scales at the weigh stations, like a caravan of tractor trailers on the interstate."
- - Another great point, because I know that I can't tell if I've drank my weight up by 2-3 lbs or dehydrated myself by the same amount. Perhaps if I've varied by 5 or more I'd be able to tell, but 2-3 is certainly enough to cause performance problems and it would be nice to know at that point so as to start moving in the opposite direction.

Interested to see what the guys in the white coats have to say on this.

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

then should we officially delete from the list of symptoms bloating, swelling and tightness of the hands and feet?

Of course not. One should not ignore such signs. But if I'm on the course and have such signs, the one thing I want to know is how much I weigh. Then I know better how to proceed.

Like you, I'm interested in seeing how others do self assessment while they're racing. I have discounted none of it as being worthless. My main point is that it is difficult to do even for someone who is well educated in what to look for, such as myself and Dev.

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Coach at KonaCoach Multisport

"I'm still in Chicago (maybe we raced against each other)"
- - Could be. I did the Mayor Daley/Americas/Chicago Marathon from '78-'83 as well as a number of other local runs.

"and sweat profusely when exercising, yet I don't feel the need for any water until I've exercised for about any hour, then it is a sip or two."
- - "Profuse" sweating is a relative term. In Chicago, where the humidity is high, the sweat stays on you, and you might think your rate is high and it may be or it might not be. Try exercising in dry desert heat and you might find your sweat rate is lower than you think.

"More than a sip of water while exercising and we get nauseous. So maybe sweat rate is not the key factor."
- - Or maybe your sweat rate isn't that high. You might be more like Dev, because of years or perhaps generations of exposure to high heat (temperatures, not the Rich Gossage fastball) might have you predisposed to cool yourself efficiently in those conditions.


"I have no scientific or medical advice to offer but, based on my experience, I don't think there is a 'one size fits all' hydration method."
- - Not until one knows one's own sweat rate in ml/min or hour, rather than just thinking that it's high. low or average. Once sweat rates are known, proper hydration strategies can be more intelligently formed. The alternative is to go seat of the pants and hope that you're in the ballpark.

I'm not saying I have the answers, but I'm enjoying pondering the questions. Some very interesting things have been said in this thread.

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

"Of course not. One should not ignore such signs. But if I'm on the course and have such signs, the one thing I want to know is how much I weigh. Then I know better how to proceed."

in this case it seems appropriate to close the disconnect between the self-diagnosing protocol that you are not sure exists, and the symptoms such as bloating, swelling, and tightness that one should not ignore. if one should not ignore them, then one is engaging in a self-diagnosis, no?

perhaps the idea might be to express to athletes the danger of hyponatremia, but also to help them preserve their races when possible. noakesians present this as a big issue, so big as to send out body language saying you may want to err on the side of what *may* yield a less-successful performance in order to preserve life and limb. if this is how noakesian medical directors truly feel, then why are there not bathroom scales lined up next to the porta potties? and at every aid station?

in this scenario, one can weigh in prior to the race, and there might be a body marker there to write that weight on the inside of the rider's upper arm, let us say. then, if the self-diagnosis of hyponatremia reveals worrisome signs, you pull over at an aid station and weigh yourself (and god help the race organizer if he chooses to buy cheap, unreliable bathroom scales).

maybe my idea is not practical. nevertheless, "one should ignore signs" means there are "signs," and "signs" is another word for "symptoms," and if you have symptoms you have the basis for self-diagnosis. if you get this far, then as medical director you can add your own infrastructure and form an end-user protocol. or am i missing something?

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Dan Empfield
aka Slowman

You have the answer. Go for a run, weigh self before and after, calculate sweat rate.
Go for long training day and hydrate according to sweat rate. See if it keeps you within striking distance of your starting weight.
I think that with all the posters here calculating watts this and watts that, and aerodynamic benefits of this and that, those of us training 10-40 hours a week could do this easily.

I love the idea of scales at aid stations, and recording weight on athlete's bodies.

Maybe we could Sharpie it onto foreheads. Or on the calf, right under age, so we can all know a bit more about each other. ; )

As triathletes we like feedback. So we wear a hrm. And we wear a watch. And some have a special hub that measures our power. And despite our training and preparation, some of us don't perform up to our potential on race day due to fluid/hydration issues.

Why not make available a way to get feedback by having a bathroom scale next to each porta-potty at each run aid station and in transition? So that when I find an available scale, such as at mile 3, I can hop on and get at least a clue as to my status *before* I develop any signs or symptoms. So that if I'm 5 lbs. up, I won't drink at miles 4 and 5 and then will re-assess at mile 6. All of this before any chance of complications. And it's my responsibility to assess this, just like I follow my hr and wattage. Not the responsibility of aid personnel. No writing of my weight on my chest each time I stop.

So in this way, I could avoid getting into an unsafe situation either hypo or hyper, and I would have a better chance at optimizing my race performance.

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Coach at KonaCoach Multisport

"maybe my idea is not practical."
- - Who cares if it's practical. It's a start. When you have a problem that can result in death, any step towards solving/minimizing that problem is a good thing. Educating the athletes is futile, because of the high number that simply won't get the message. Educating the RDs who can in turn educate their staff and volunteers is better.
We get new folks in the sport all the time, and even the most zealous and knowledge-hungry are likely to NOT get this information until they've been in the sport for several years, by which time they may be learning it the hard way.
It's discussions like this that make Slowtwitch the most incredible website in all of Internetdom. There is a possibility that this discussion just might lead to something changing out there in triathlon land. That would be awesome indeed.

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

Interestingly the recent Missasauga Marathon provided scales at the start and finish to help assess risk of hyponatremia.

http://www.mississaugamarathon.com/...er/2007_issue7.htm#3

"See if it keeps you within striking distance of your starting weight."
- - OK, but as mentioned elsewhere on this thread, you can lose weight without affecting your fluid and electrolyte balance. So is 3 lbs a safe amount to lose? When evaluating my sweat rate, should I shoot for stasis or for a loss of X%? and if X% should that be X% per hour, per mile or total for the day?
I've always aimed to finish a long day (5 hours or more, so century and above, HIM and longer or big training days) at the same weight that I started, but after reading some of the things here, I'm now convinced that I've been overhydrating. This is also consistent with how I've often felt at the end of those long days (somewhat bloated/overfull).

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

"Maybe we could Sharpie it onto foreheads. Or on the calf, right under age, so we can all know a bit more about each other. ; )"
- - Good. Also measurements (gotta check to see if the weight loss/gain is just in the belly or if the joints or specific body parts are swelling, uh, well, um... I mean like ankles and wrists) and don't forget bra size and marital status (you know, so we know who to contact...). Yeah, vital signs and stats on the calf, then spray liberally with Pam and away it all goes!
The forehead might be the best place, because it's likely not to have tatoos, except for Dennis Rodman and Mike Tyson...

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

Dan,
It has been fun to be an observer of this thread and in my opinion, getting some better usefulness of opinion than this same stuff last week.
Talking about Noakesian versus not is rather foreign for most physicians as this is old stuff for those of us who really treat severe hyponatremia in ICUs .... reading "sports medicine" journals becomes sort of meaningless when the issues and all their complicating factors have been addressed in core medical publishings for 30+ years. Not to belittle the findings, but Noakesian philosophy as you call it shouldn't be a surprise to any MD ... rather the expectation.
Published "laboratory" studies might sometimes be helpful .... but many times are misleading because the right question isn't being asked or the conditions are different from the real study group being looked at. I think this makes Andy look silly at times in my opinion because he takes his "results" too liberally .... what about those salt pills Andy??
Bottom line ... if you want to be better accurate about hydration status ... use a scale. I personally would use it every race coming out of T2 even though I've learned by trial and error how to take care of myself.
It also is clear that hyponatremia is a potentially bad condition, but the vast majority of people in the medical tent are dehydrated ... usually GI related. In spite of our theoretical discussion that this shouldn't affect performance ... they end up requiring the "tin can transfer" as their legs don't seem to work. All the fluids are being given for that reason in medical tents. Dev's issue should have been noticed by his weight gain ... if that pre-event weight we all get was really ever seen by the medical staff ( I suspect that it wasn't or fluids wouldn't have been given to him).
This is good stuff for those who want to be in better control of their IM distance race hydration.
Dave

"Why not make available a way to get feedback by having a bathroom scale next to each porta-potty at each run aid station and in transition?"

i'm all for it. the thing is, if we had to stop, leave the course, and stand at attention for several seconds, to get our heart rates, i have this suspicion we'd be racing without knowing our heart rates. but i could be wrong. you may be right. in this case, all you'd need to know is how much you weigh prior to the race, and then you step on the scale at some point mid-race.

but, let's say that my cynical view turns out, unfortunately, to be the truer one, that athletes in the heat of battle are not going to stop in any significant numbers to weigh themselves during the race, absent some very good reason. i think it best if we can find a way to help them determine that very good reason, and that is a way for the athlete to self-diagnose an impending problem.

keep in mind that in each of our scenarios there still needs to be a bathroom scale at every aid station, next to every porta potty, and probably a few scales at the start of the race.

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Dan Empfield
aka Slowman

"there still needs to be a bathroom scale at every aid station, next to every porta potty, and probably a few scales at the start of the race."


I think thats way too complicated and all of them would have to be calibrated as well. No one needs a weight after the swim. No one is going to stop on their bike, get off, and get weighed.
I don't think anyone needs a weight before T2 ... you could just have 3 or 4 scales at the outrun from T2 and everyone is getting pretty well spread out by then even with NAS IM races and 2200 people. You could even put them on the start of the run course if its a multiple loop course and you could use them twice. Weigh yourself on them before the race for your baseline. Not a big deal at all. Obviously not everyone will use them ... but they would if they were smart!
Dave

The very good reason would be not feeling great, and considering dehydration as the source of all life's woes.
The racer would think, "I feel terrible . . . am I dehydrated?" The next thought would be, "I should weigh myself."
Racer weighs self. Uses that info to influence ongoing hydration strategy.

I also agree on the point that you wouldn't need scales in T1 or the bike, but T2 and the run would be nice, since most drinking occurs on the bike and you would know your weight heading into the run and thereafter.

"I also agree on the point that you wouldn't need scales in T1 or the bike, but T2 and the run would be nice, since most drinking occurs on the bike and you would know your weight heading into the run and thereafter."

i would not know my weight to within 4lb or 5lb on race morning, unless i've been weighing myself regularly (which i do not). hence my comment about scales at the start of the race. i'm talking about 20 or 30 or 40 minutes before the start.

plus, athletes get stupid when they race. i don't know how many ultras you've done, but i can remember hitting, say, 9mi, and having a VERY hard time figuring out what 26 minus 9 equals. and then doing the math all over again at mi-11, and mi-12. hence my comment about writing the pre-race weight down. on the athlete.

all this is predicated upon the view that hyponatremia is as prevalent and serious as you all say it is. i'm stipulating to that, for the sake of the discussion, and trying to come up with some ideas that parallel that threat.

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Dan Empfield
aka Slowman

The real question is even if the scales are there, how effective would they be. First how many people are going to stop even if they weigh themselves? I'm guess not many. How could it be accurate? A humid day is going to make it difficule somone who's cloths are saturated with water may not look like their weight has changed, or it might look like they've gained weight when they didn't.

The real focus should be on teaching people how to hydrate properly. Getting a handle on your sweat rates should be as important as your training when you're talking long distance racing. Making blanket statements is just dumb either way.

The clothing point is a good one, but with the gear people wear today, how "wet" do they get? Cotton, yes. Space-age wicking synthetics? After run here in Philly they often feel a bit damp, but no more.

Agree about sweat rates.

Think it depends on the type of gear and the humidity. So me a really heavy sweater on a humid day with a loose shirt it can be an amazing amount a water weight. I've had cycling jerseys weigh several pounds after I've taken them off on a "bad" day. Something like a trisuit with nice micro fabric, not so much. Remember pure water weights ~ 1 pound per pint.

 
You could use an RFID chip for the timing chip. Every athlete stands on a scale as they're getting body-marked. It gets fed to a wireless network with a reader in each medical tent. Somebody comes in the tent, a simple scan will tell the MDs the relevant info...

Or the athlete could just say "I usually weigh 160lbs".

Dave, in fairness to the medical staff at the med tent at IMLP 2003 (and I'm not one of those to try and sue an event or staff for my own friggin mistakes that brought me to the med tent in the first place....), the place was like a mash unit. If the person treating you does not know what you are supposed to look like to start (140 lbs vs 150 lbs), and for some reason if the "before" weight (140) was not compared with the "after" (150), then the various symptoms that the athlete is reporting could be very well interpreted as those from dehydration (like the bulk of people that show up in the "mash unit"). In 2003, the docs were more worried about Chis Legh type "loose half of your intenstine from severe dehydation" than "that guy might die from hydration!!!

I BELIEVE, thanks to my escapade, Ironman North America is much more aware of this type of scenario (after much behind the scenes correspondance) and the medical staff is really briefed on this type of situation.

Keep in mind that many of the medical volunteers might be GPs whose specialty is not dealing with severely hyponatremic patients in the ICU.

Dev

Several points. First, what we'd all like but we're not going to get is a single, simple, reliable indicator with an absolute interpretation. Humans, being biological beings and not machines, tend to not exhibit such indicators; this is axiomatic throughout the field of medicine. Rather, there are clusters or "constellations" of signs and symptoms (and those words are not synonymous) for various conditions, and interpretations are made in the context of these constellations. So scales may be a useful element, but that's not the whole story. Fluid in my stomach (that I may be about to vomit), fluid in my plasma, and fluid in my third space all look the same on the scale. Further, many of the other indicators can be difficult to detect or interpret, even for physicians.

That said, though, I love the idea of scales as a first iteration measure. Weigh yourself at T1 and again at T2 on the same scale (the one you brought with you). But interpret that result in the greater context: what have you been drinking on the bike? How do you feel? Is your stomach sloshing? In a long event, I and probably many others would find this to be very useful and reassuring information. For those who become ill during the event, scales alone aren't enough, but they'd be an extremely useful element, especially if we take seriously the suggestion to sharpie the pre-race weight right onto the skin of every competitor.

Also worth mentioning is that since we don't yet have full agreement about optimum hydration strategy for either health/survival or performance, we're also not ready to distinguish between the two. But logically, a strategy that is physiologically optimum for circulatory health is likely to simultaneously optimize survival and performance.

Interesting thread.

" I did the Mayor Daley/Americas/Chicago Marathon from '78-'83 as well as a number of other local runs."

Did those in 1980 and 1981. That's where I first learned that I shouldn't drink water at every aid station. Do you remember the Marine band on Wells street. Very inspirational at mile 5; annoying as hell at mile 23.

As I mentioned in an earlier post, I do this on every single workout. It just makes logical sense, especially after getting badly dehydrated on one race a few years back. I can now easily recognize the signs of dehydration, and with my sweat rate it's nearly impossible for me to get hypervolemic.

Regarding the scales and weight numbers, at some races they sharpie your prerace weight on your race number. That way if you show up at the med tent 5lb over your prerace weight the docs should have the info to know that you do NOT need a bag of IV hydration. This seems like a very important thing for race directors to do, and very trivial to actually implement it. Adding a cheap $10 scale at every aid station or something isn't a bad idea but not always practical. Having several at T2 would be really nice.

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"Do you remember the Marine band on Wells street. Very inspirational at mile 5; annoying as hell at mile 23."
- - My memories of that are sketchy. I remember a lot of music all over the coure (mostly boom boxes) and a couple of bands. One year (I think it was '80 and Howdy-Doody look alike Jane Byrne changed the name to "America's Marathon" instead of the "Mayor Daley Marathon") and everyone was playing the theme from Rocky. I got pretty sick of that song by the end of the race. I also remember an old guy who had done the race nearly every year. He wore his age for a race number and that year I think he was 77, Vic something... Funny how you remember certain things... I also thing that '80 was the second or third year that they had Gatorade on the course. I'm pretty sure we just had water in '77.
Chicago was a marathon that I really liked, because it was a fast course and interesting.
I used to live out in Indian Lakes (Bloomingdale). I really felt special, because we had a hill going in and out of our subdivision. Of course with an elevation gain of about 70 feet, no one in CA would call it a hill, but it was enough that I felt like it gave me a place to do "mound repeats." There was also a hill in Medina that could actually pass muster anywhere (not that it was huge, just that when you called it a hill, people didn't look at you funny), but it was a four-mile run to get there.

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

Noakes here.

Thanks for the generally excellent level of debate, marred by the inevitable personalisation of argument especially by those who have nothing better to contribute. May I be allowed to make a few comments.

The first case of (near fatal) exercise-associated hyponatremic encephalopathy (EAHC) happened in the 1981 56 mile Comrades Marathon in South Africa. Although I was involved in a research project in the Comrades medical tent on that day I did not personally see the patient. However she wrote to me a few weeks later to ask my advice. I told her that I had absolutely no idea what had caused her EAHC. Over the next 3 years I interviewed another 3 athletes who had developed exercise-associated hyponatremia (EAH). On the basis of that information, a series of calculations and 3 years of contemplation and reading the literature, I concluded that the condition occurred in athletes who ingested too much fluid during exercise. This was described in a paper published in 1985. In an editorial that accompanied the reprinting of that, by then, classic paper 20 years later, the author wrote that: “Tim Noakes was right 20 years ago and the passage of two decades has done nothing to diminish the accuracy of his conclusions”.

To evaluate our 1985 hypothesis we next completed a prospective, controlled, in-hospital study of 8 athletes as they recovered from either EAH or EAHC developed during the 1988 Comrades marathon. This study published in 1991 proved our 1985 conclusion since it confirmed that all these athletes were over-hydrated by between 2 and 6 litres (4-12lbs). Furthermore we also established that sodium depletion played no role in these cases since their sodium deficits at the end of the race was not different from those that developed in a control group of ultra-marathon runners.

What normally happens in medicine is that such evidence is pretty quickly absorbed and become the mainstream practice. But in this case, this did not happen. Instead I discovered that I became the target of a subtle disinformation program that apparently still continues today, judging by some comments on this blog. I found that I was no longer welcome at certain conferences or athletic events, funded by certain organisations. So I was cast as an evangelist, a religious zealot, someone who ignored all the published evidence that did not agree with his particular “religion”, and an iconoclastic egoist who was more interested in fame than in being correct.

Interestingly at the very time that I was being so typecast, the advice to endurance athletes became that they “should drink as much as tolerable” in order to prevent “dehydration”, heat stroke and an impaired performance. So instead of warning athletes of the dangers of overdrinking, conditions were developed which encouraged overdrinking. Whether or not this was the intended outcome, this was indeed the result as so clearly described by Devashish Paul. (Of course, when athletes like Devashish developed the condition it is natural that they should be blamed – as has occurred in this thread - and not those who gave them such dangerous advice). But it did not take a genius to predict what would be the outcome of this advice to “drink as much as tolerable”. And so predictably people died as a result of this advice. At present, an absolute minimum of 11 avoidable deaths, the majority in marathon runners and army personnel in the US, have occurred; the most recent at the 2007 London Marathon. In contrast in those scientifically-backward countries like South Africa and New Zealand where my opinion and that of my co-researcher Dr Speedy have credence, there have been no deaths from this condition and EAH and EAHC has essentially disappeared. With this background it is perhaps appropriate to correct some errors on some submission on this thread.

Philbert makes that error of labelling me an evangelist which is dismissive and unnecessary. The information I have presented since 1985 is based on hard evidence and is now known to be true. My understanding is that evangelists wish to force a personal belief on others, whether or not that belief is “true”. I studied EAH and EAHC for 10 years before we published the definitive evidence that the condition is due to overdrinking without evidence for sodium deficiency. Only thereafter did I become rather more vociferous in my opinion especially when what I had predicted would happen – avoidable deaths – began to happen. As a doctor my first responsibility is to do not harm. If I know that unnecessary harm is being done as a result of ignorance, I have an ethical responsibility to do something about it. If the price of that activism is to be labelled an evangelist, then perhaps that is a small cost.

Philbert also claims that there were many nephrologists saying the same sort of thing before “Noakes really got any steam behind him”. Again this is dismissive besides being untrue. There is no evidence in the published literature that “many nephrologists” were “saying this sort of thing” at the time of our first publication in 1985. How could they have since the condition was unknown at the time? And if the mechanisms were already so well understood by so many, why is it that so many avoidable deaths occurred in the US between 1993 and 2002, fully 17 years after our first publication? There is a saying that science goes through three phases: First they say that what you say is nonsense. Then they say that what you say is correct but it is irrelevant. Then they say that what you say is true but we have always known it. I appreciate Philbert’s support that we are now in the third phase of the truth of EAH and EAHC but he should be more circumspect in his descriptions of others, particularly if he is not in command of all the facts.

Like many others, I have knocked heads with Dr Coggan frequently over the past 20 years but never on the question of fluids and exercise which, in my understanding, is not within his area of expertise. My review today of his publication list on PubMed reveals that of the 59 listed papers he has published between 1984 and 2007, not one is on fluid balance during exercise. Thus I am surprised that he considers himself to be such an expert on the topic. But I am most relieved that in those 23 years he has not lost his venomous tongue, nor his capacity to use insults as his main weapon of argument. So he claims that I (not he) have not “conducted a single experimental study to support his (ie my) claims”. To combat my abject ignorance he advised that I should do more than just “skim through a few papers and/or chat with a few graduate students to understand the real story here”. To overcome their ignorance, visitors to this blog are also advised that: “you have to dig into the data and base your conclusions on what it actually shows (vs what a self-described iconoclast such as Noakes claims it shows)”.

In my defence, I would suggest that readers should access PubMed to see for themselves whether or not I have done any laboratory studies of fluids and exercise or whether my ideas of the etiology of EAH and EAHC are based solely on a fantasy driven by the egocentric need for a personal aggrandisement so that I can be “iconoclasatic”. (Actually it was a prominent member of the Gatorade Sports Science Institute who first labelled me as iconoclastic, not myself).

Not only has Dr Coggan never undertaken any studies of this topic, but he enjoys the rare privilege of the laboratory exercise scientist – absolute immunity from responsibility for any outcomes resulting from his advice. However in my position as a medical doctor and medical director of a number of ultramarathon and Ironman triathlon races over the past 30 years, I do not enjoy such absence of responsibility. Rather I am accountable for any adverse outcomes that result from the drinking advice that I give athletes in these races and for any treatments that they might receive, based on those opinions. So I am glad to report that the Ironman Triathlon races at which I was the medical director had the lowest reported incidence of post-race medical admissions of any such race on record and a negligible incidence of EAH and EAHC.

But Dr Coggan, who really understands, claims that: “Noakes is, to be blunt, someone who would apparently be just as happy to be known as being right. That is, IMO he is overly willing to ignore data that contradicts his unusual points of view (plural, because this is but one of many issues on which Noakes has adopted a position that is contrary to the evidence… as mentioned before he himself says that he’s an iconoclast”.

Later his insulting diatribe continues: “No, I think that Noakes is a true believer in his own religion, i.e. he’s not tailoring his message to try to achieve some altruistic goal”.

Surprising then that when we apply this incorrect, unscientific, egotistical knowledge purely for the purpose of self aggrandisement and without respect for what is really “true”, we deliver results that no other Ironman race has yet recorded and, in addition, we have an essentially negligible incidence of EAH and EAHC. Perhaps this is the kind of untrue “religion” that others should be adopting rather urgently.

Probably Dr Coggan is not aware that in November 2006, the Runner’s World (USA) magazine voted our work on EAH as one of the 40 most important “people or events” of the past 40 years in running. Which is not bad for work originating outside the United States of America. Such recognition suggests that at least some people consider that this work is rather more than that of an egotistical iconoclast who “just wants to be known”, whether or not he is right.

A great deal of the discussion is based on the concept that the body defends its weight so that if the weight is measured, then the correct drinking guidelines can be arrived at. In fact the body defends its osmolality through the thirst mechanism, and not the body weight. Thus the presence of thirst indicates that the brain considers that the osmolality has changed sufficiently to require correction. We have shown that the extent to which thirst develops is under genetic control so that some drink avariciously during exercise whereas others drink hardly at all. In an upcoming debate with the gentlemanly Dr Michael Sawka to be published in Medicine and Science in Sports and Exercise, I present the argument that the reason why exercise performance is impaired in persons who drink less than their thirst dictates during exercise is not because they are “dehydrated” but rather because they are thirsty.

According to this logic and supported by all the published evidence (including 2 studies of our own of which Dr Coggan appears ignorant – see also my recent article in the Journal of Sports Sciences), exercise performance is maximizes in those who drink enough to avoid thirst during exercise regardless of how “dehydrated” they become. Thus some will be thirsty when they are 2% dehydrated and others will not be thirsty even if they lose 6-10% body weight (as our data on Ironman triathletes seems to show). Interestingly in our as yet unpublished study we show that simply telling people they will not be drinking during exercise impairs their performance right from the start of exercise (that is in anticipation) and before they have become "dehydrated". This shows that the way in which not drinking affects performance is a little more complex than currently understood.

Finally there is now good evidence that humans evolved as long distance runners on the African savannah and that our ability to sweat (and become dehydrated) allowed us to outrun faster antelope whose inability to sweat (and to become dehydrated) prevented them from maintaining low body temperatures during very prolonged (4-6 hours) exercise in extreme dry heat (between 40-46 degrees Centigrade; 104-115 degrees Farenheit) when both had limited access to water. The most effective hunters would be those who developed the least thirst despite high levels of dehydration since they would have been the most likely to continue running for so long and therefore most likely to kill their quarry.

This evolutionary model predicts that the best endurance athletes will therefore be those best able to run without becoming thirsty even though they lose large amounts of weight. The low drinking rates of most of the world’s best endurance athletes in marathon, ultramarathon and Ironman triathlon races provides anecdotal support for this surprising hypothesis.

To follow a 4 hour hunt with minimal fluid replacement by the !kung San (Bushmen) in the Kalahari desert at 46 degrees Centigrade, readers might wish to view The Great Dance – a hunter’s story (http://www.rapidblue.com).

That is my story. I will not respond further but in future scientific publications on this topic. So you are welcome to say what you wish.

Wow!! Thanks, and welcome to the jungle......

Second that "wow."
And the thanks.

Fight, Fight...! <pulls back chair, opens beer>

I feel a classic thread coming up...

Any thoughts on powercranks btw Tim?

Dear Dr. Noakes, it truly is a small global endurance sport village and thanks again for your great advice that helped me post IMLP2003.

I am particulary interested in some of your points which I have pasted below:

"Finally there is now good evidence that humans evolved as long distance runners on the African savannah and that our ability to sweat (and become dehydrated) allowed us to outrun faster antelope whose inability to sweat (and to become dehydrated) prevented them from maintaining low body temperatures during very prolonged (4-6 hours) exercise in extreme dry heat (between 40-46 degrees Centigrade; 104-115 degrees Farenheit) when both had limited access to water. The most effective hunters would be those who developed the least thirst despite high levels of dehydration since they would have been the most likely to continue running for so long and therefore most likely to kill their quarry.

This evolutionary model predicts that the best endurance athletes will therefore be those best able to run without becoming thirsty even though they lose large amounts of weight. The low drinking rates of most of the world’s best endurance athletes in marathon, ultramarathon and Ironman triathlon races provides anecdotal support for this surprising hypothesis."

I'd like to bring up an associated point which I kind of joked about in a posting above. You mention that there might be an evolutionary thing here, in that the best might be able to continue running for a long time with low sweat rates despite dehydration. I want to bring in this relationship between dehydration, rapid fluid ingestion and SIADH kicking in. Let me explain further. In many Ironmans, athletes spend 60+ minutes in a long sleeve wetsuit, in warm water temps which arguably should in many cases be wetsuit illegal. They exit the swim dehydrated and soon start pounding back liquids.

Let's take a step back to that human ancestor of ours, outrunning the antelope. Now, I would guess that our evolutionary mechanisms do not take into account the ability to drink while exercising and severely dehydrated. The ancestor of ours had no drinking options on the fly. Only when he stopped and was safe, was he able to take in liquid. Until then, his kidneys were "shut off" to conserve liquid.

Move back to modern day triathlon. You are dehydrated from the swim. The kidneys are trying to conserve liquid...you hit multiple aid stations during the bike, and are still dehydrated...you take in several liters over say the first 90K....but your kidneys are not processing this stuff. SIADH has kicked in. It is cool and you are not sweating either....suddenly you are several lbs overweight.

What are your thoughts?

Anyway, I would really like to see you publish an article with Slowman and any others on this topic. I'd be glad to participate in any way and get it out to the mainstream triathlon publications if it helps save people from near death ordeals and 4 years of gradual recovery.

Any logical evidence of over-hydration will be thrown aside ,due to the huge business in hydration gear . Sports drinks and bottled water , how did people survive a few thousand years without them , amazing .

How much truth can you afford .

I agree, however I just pulled up the Gatorade site and even they include a disclaimer not to overhydrate. Maybe Dr Noakes and his disciples are getting through to the Hydration Industry afterall.

BTW, it was very cool that Dr. Noakes came on board to defend his position. But how did he know he was getting dissed on Slowtwitch? Dev...?

3rd the wow.

Tim you forgot to pick up your free coupon before you subscribed o the forum. :-)




Andy come out to plaaaay. Andy come out to plaaaay.

"I would really like to see you publish an article with Slowman and any others on this topic."

Empfield (me) PM'd and emailed Noakes w/questions. obviously, he's much better able to answer my questions which, notwithstanding his comprehensive answer, are still open. they relate to in-race self-diagnostics; whether there's a difference between a hydration protocol that is safety-specific versus performance-specific; and the much-ascribed to him ambivalence to in-race salt intake. i hope he will answer, in particular because the Noakes views that i have read are directed to the care giver, medical director, etc., that is, there's not yet a lot of meaty stuff the athletes can hang onto past, "don't drink if you're not thirsty." yes, there are personal-sweat-measuring tools, but i'm not sure to what degree that falls down when i, who live in the high desert, have as my A race an event in kona. there must be more for the end user. therefore, i look forward to the answers and hope they come.

as for man v antelope, for all the respect i have for the doctors who're on the front lines doing the research (noakes and coggan among them), i've got a problem with the pre-history analogies. as regards race protocol, ought i to warm up before i commence? did my ancesters? further, i'm german/scot. did my ancestors adapt to a different way of life, and ought my fluid protocols to likewise alter, or not? you, dev, made mention of the adaptations you suspect your ancestors made to its exceptionally humid clime, and this (you think) caused you to react differently than would, perhaps, i. were i to follow the prehistoric DNA argument, i must assume my mojave desert (where i live) diet should consist of acorn mash, pine nuts, and the fly larvae lining the bottom of mono lake. if my stomach can't withstand native american diets (it can't), and the native american can't be healthy eating as a european does (he can't), is it appropriate to assume digestive systems have changed but all-things-hydration have not? i'm not using this to argue against the Noakes protocols for hydration, i'm just not a huge fan of basing medical advice on how my ancestors survived 1 million years ago.

that established, i'll bet i could catch the antelope. how to start the fire needed to cook it, that's where i'd fall down. i don't think we're done with this discussion yet.

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Dan Empfield
aka Slowman

Previous thread along the same lines.

Old post 11 of 28 Link

"This evolutionary model predicts that the best endurance athletes will therefore be those best able to run without becoming thirsty even though they lose large amounts of weight. The low drinking rates of most of the world’s best endurance athletes in marathon, ultramarathon and Ironman triathlon races provides anecdotal support for this surprising hypothesis."

Aha! I tell that to my spin instructor the next time she tells me I should bring a water bottle to class.

BTW - Does this make me higher or lower on the evolutionary ladder? I really don't need to hunt since we have a lot of grocery stores nearby.

Thanks for a great and informative post. The above is particularly interesting to me because I noticed a similar phenomenon with hunger while training. It really wasn't provable until I had a powermeter, but if I am out on a long ride (say 80+ miles) and don't eat enough solid food (Powerbars or pretzels, etc) I can be fine riding 200-220W...until my stomach growls. It's like an instant 20W hit in output that lasts until I eat something solid, Gus and drink mix don't seem to have an effect. In this case maybe it's simply the body saying "you are starving to death I am reducing your energy expenditure."

At any rate, I only wish my thirst mechanism was even remotely well tuned. When I started keeping track of before and after workout weight I found myself surprised many times by how little or how much I had lost, frequently without any substantial increase in thirst. There were several times during a longer (10-15 miles) run where I would suddenly stop sweating, and of course my body temp soared, I'd make it home at substantially reduced speed and discover that I'd lost 4-5lb...and still not be really thirsty. Other times I'd be really thirsty and drinking much larger amounts of water than normal, still run or bike fast and come home losing only 1-2lb. In other words, there doesn't seem to be a clear correlation for me between thirst and performance, but a definite correlation between dehydration and performance.

I'll have to keep track of this tomorrow, forecast highs in the 90s and the typical Floriduh sauna humidity. I'll see how 80+ miles feels!

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You just never know who will show up on Slowtwitch! Thanks for joining the discussion, and sorry to be late back to the game. I lost track of this thread and just learned of your post. Though you say you will not respond to further posts (which is unfortunate, as you have a lot to contribute), I wanted to respond for the sake of the completeness of the thread.

Your point is well taken regarding the EAH in the literature. However, in this instance I was not referring to the literature. Rather, I was referring to a rather crusty internist/nephrologist I encountered during my early training, who first brought your work to my attention. I may be taking some liberties with his exact words, but his response to my questioning was along the lines of, "You know, a lot of us were discussing this before Noakes was publishing so much. Fortunately, Noakes is now making it common knowledge. You should read these papers, they will keep you from killing people." I made the (perhaps erroneous?) assumption that this was something that had been kicked around at nephrology meetings before you began publishing so widely on the subject.



Perhaps "evangelist" is the wrong word. I did not mean to be offensive. Rather, the point I was trying to make is that you tend to argue your points rather voiciferously. For the record, while working the medical tent at a marathon a couple of years ago, I was labeled the "Sodium Nazi" by a couple of ER residents who were hot to stick large bore IV's in everyone who walked (or was carried into) the tent. I think Dev and I discussed that incident at one point...

In any case, I think I made it clear in my comments that I think your work on EAH has been a great public service, and I stand by that. In fact, a few of your papers are required reading for the medical students and residents who attend my lectures on EAH, heat illness and exercise associated collapse. They are also cited in my book, on account of which I still occasionally receive angry e-mail from coaches and athletes who explain to me the need to drink "as much as is tolerable". You can't convince some people...

Phil

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Dr. Philip Skiba
Scientific Training for Endurance Athletes now available on Amazon!

Thanks for your generous response. You are a true gentleman.

With warm regards,

Tim Noakes.

Dear Dan,

You asked so nicely that I could not justify not responding.

Before I begin it might be helpful to add some other biographical data. I began running in 1969 at the time when we were advised to avoid drinking during exercise. I spent much effort in the 1970’s trying to change that advice and even wrote some articles on this topic which were published in two running books in the US. But when we saw the first cases of EAH in South Africa in the early 1980’s, I realised that the pendulum had swung too far and that we had to qualify the advice we were giving.

Over a 21 year period I completed more than 70 marathon and ultra-marathon running races and a host of other standard triathlons and cycling races. I did not ever finish a race feeling thirsty. When I performed less well than I expected, the diagnosis was never very difficult. Since I always drank the same amounts, changes in my drinking behaviours could not have been the cause for either my better or worse performances. Rather the obvious cause was my preparation; when I performed well my preparation had always been ideal. I often wonder if, when we perform poorly, we look for an easy scapegoat. So, for example, we explain our underperformance on the basis that we must have drunk too little water or salt or whatever. How possibly could our preparation have been at fault? This inability to be self-critical provides fertile soil for exploitation by commercial forces.

On the other hand, as described in Lore of Running, I underperformed on a number of occasions when I failed to ingest enough carbohydrate and developed the symptoms of hypoglycaemia (low blood glucose concentration). I concluded that, especially in events lasting more than 2 hours, carbohydrate intake had a much greater impact on my performance than did my rate of fluid ingestion.

This may seem obvious today but before the mid-1980’s we did not believe that ingesting carbohydrate during exercise aided performance – all the emphasis at that time was on fluid ingestion being the crucial determinant of performance. We had to learn from personal experience that carbohydrate ingestion during exercise was perhaps even more important than fluid ingestion. This was confirmed in the laboratory for the first time only in the late 1980’s.

Now in answer to your questions.

1. Is salt intake necessary during prolonged exercise like the Ironman.

The short answer is that no one has yet provided good evidence that salt intake beyond the homeopathic amounts present in sports drinks is necessary to sustain performance during something like the Ironman. This does not mean that the case is conclusively proven; just that there is no definitive support for this practice at present. Interestingly our and other’s data suggests that the body probably has a reserve of sodium stored in an unionized form, perhaps in bone and skin, that can then be activated in the short term should a deficit in the blood sodium content develop. However this is still a controversial issue.

But more to the point is the absolutely clear evidence that subjects who drink to thirst will maintain or increase their serum sodium concentrations whether or not they ingest salt during exercise. Only in those who drink in excess of thirst and who either maintain or increase their weight during exercise is their some evidence that the extent to which the blood sodium concentration falls will be reduced (but not prevented) by the ingestion of sodium during exercise. (This fall can only be prevented by drinking less). Of course this finding has been seized upon by the sports drink industry as absolute evidence that sodium ingestion is essential during exercise. What they have failed to say is that if athletes just drank less during exercise (ie to thirst), they would not need to ingest salt in order to maintain their blood sodium concentrations. This we have known since blood sodium concentrations were first measured in runners in the 1960’s.

We have also shown in two separate studies that salt ingestion does not influence the blood sodium concentration in Ironman triathletes who drink according to thirst. In a series of laboratory studies we also failed to find any real evidence for a major beneficial effect of sodium ingestion during exercise of short to moderate duration (up to 3 hours).

The main benefit of sodium ingestion is that drinks with sodium (and glucose) are usually more palatable than are those without salt in the relatively low concentrations - less than 20mmol per litre - that athletes find palatable during exercise.

In the past month or so, my colleague Dr Tamara Hew has taught me something which may be of critical importance. On the basis of some interesting and preliminary data, she has concluded that the body must regulate its sodium losses during exercise, probably in order to protect the blood sodium concentration. In other words, the amount of salt that is lost in sweat during exercise is not a random phenomenon but must be tightly controlled. It is common knowledge that the amount of salt lost in urine is tightly regulated by different hormones and is one of the key functions of the kidney.

But during exercise, the main site of salt loss is in the sweat, not in the urine. Why would we believe that this loss is not just as tightly regulated as is the loss of sodium in the urine? It does not make sense to think otherwise.

So Tamara’s conclusion is that the amount of sodium lost in the sweat must be controlled just as is the amount of water that is lost, and all are regulated to insure that the homeostatic balance in the body is protected as best as possible. We know that the amount of water that is lost as sweat is regulated in proportion to the elevation in body temperature (or the rate at which heat is being produced); the amount of sodium that is lost must be regulated in order to minimize changes in the osmolality of the blood (at any given sweat rate). In addition, the body seems to have the capacity to remove or add sodium into the blood stream from an unionized (stored) form; this would provide another buffer against sudden changes in blood sodium concentrations (and osmolality) in persons who are sweating profusely during exercise. Depending on the interactions between all these different processes, so athletes will either sweat more or less and drink either more or less during exercise.

The point of all this is perhaps to suggest that the body is designed as a complex system and when one tries to analysis it too simplistically, the conclusions that one draws may be wrong. The clearest point is that we are genetically different and will respond quite differently to the same stresses. Thus some unable to defend their serum sodium concentrations and osmolality will become thirsty at low levels of sweat and water loss whereas others will protect these variables so well that they will not become thirsty until they have lost substantial amounts of body water (since it is the change in the osmolality of the blood that determines thirst).

But given the freedom to choose, the body will tell you when you need water (you will be thirsty) and when you need salt (you will develop a salt-craving). The ruthlessly selective processes of evolution provided us with these essentially fail-safe controls. We just need to learn to listen to and to obey them. And not to assume that general advice will be ideal for everyone.

2. Are my drinking guidelines aimed at safety or performance and would the advice be the same for a Kenyan trying for a sub-2:05 marathon as for an Iowan trying for a sub-5-hour marathon?

To be facetious, the Kenyans do not need any advice. A study we have completed with a group of elite runners in Eldoret, Kenya and which is currently in review, shows that they drink very little during both training and racing. Under all conditions, they drink according to their thirst and it seems that they must have a high thirst threshold since they drink so little (ie they must be able to protect their serum osmolalities very well despite large losses of body water). Their approach fits nicely with the evolutionary hypothesis that the best hunters were likely those with the highest thirst thresholds and who had a lesser need to drink during exercise.

Of course the usual answer from the advocates of the “drink as much as tolerable” school is: “Imagine how much faster the Kenyans would run marathons if only they forced themselves to drink more!” I have spoken to our very best South African (2:07) marathon runners and they are all of the same opinion – it is not possible for them to drink more than about 200-400ml per hour (7-14 oz per hour) when running at 3 minutes a kilometer; nor do they feel the urge to drink more; nor do they see that drinking more would be of any advantage. One such runner told me that as he loses weight during the marathon, he feels lighter and faster.

I would guess that a 5 hour marathoner sweats at a rate of about 300-400ml per hour (about 10-14 oz per hour) and would not likely drink less than that since he or she run so slowly, each has so much time to drink. In addition these slow runners have usually been advised that the fatigue they feel can be prevented by drinking more. Rather, in my opinion, they would probably benefit by being told that they need to be careful how much they drink during exercise.

In summary, then, the advice to the best and the slowest is exactly the same. Drink to thirst and you will optimize your performance. This conclusion that drinking according to the dictates of thirst optimizes performance is also supported by all the published literature (see my recent article in Journal of Sports Sciences and my debate with Dr Mike Sawka to be published in Medicine and Science in Sports and Exercise in the next few months).


3. Mid-race diagnostics for the detection of hyponatremia.

Again, if you follow the advice of drinking only according to the dictates of thirst you cannot become hyponatremic unless your concept of thirst has been modified by all the information given to athletes so that you actually drink in excess of thirst.

So if you are drinking according to your real thirst and you feel lousy mid-way through a race, it will not be because you are hyponatremic. Nor, incidentally, will it be because you are “dehydrated”. Something else will be wrong (perhaps you did not prepare properly; or you went too fast in the first half of the race; or you are ill).

If you have been drinking in excess of thirst and you think you are hyponatremic, there will usually be corollary evidence to support your diagnosis.

First you will probably admit that you have been drinking in excess of thirst.

Second, you will probably feel bloated and may even hear the sloshing of fluid in your intestines. This may also cause you to feel nauseous. You may vomit clear fluid. The latter is a very strong indicator that the rate at which you are drinking exceeds the capacity of your intestines to absorb that fluid. This will usually mean that you have been drinking well in excess of 1000ml (36oz) per hour.

Third you may notice that your watch strap or ring or race bracelet has become tighter.

Fourth, you will notice that your level of consciousness is altered and that you have difficulty concentrating.

If any of these develop, stop drinking until these symptoms and signs disappear (which will likely take some hours since your fluid overload at this stage would likely be at least 2000ml (72oz)).

B. If you are hyponatremic and you stop drinking the condition will reverse itself.

The problem is that once the brain starts to swell significantly as a result of this accumulated fluid overload in someone who continues to ingest fluid at a high rate (or who receives intravenous fluids as treatment for an erroneously diagnosed “dehydration”), brain symptoms may advance rapidly so that the athlete may go from being mildly confused to developing seizures and becoming unconscious quite suddenly (within minutes) with the risk that the athlete may stop breathing.

We advocate the use of slow (at rates of approximately 100ml per hour) intravenous infusions of high salt (3-5% sodium) concentrations once brain symptoms are present. Such infusions can produce miraculous recoveries in some confused hyponatremic athletes whose confusion can be reversed, as if by miracle, within 5-10 minutes.

To summarize: The rules of drinking that we advocate are the following:

Drink if you are thirsty.

Do not drink if you are not thirsty,

Avoid all out racing efforts when the environmental conditions are severe, especially when it is both hot and humid. If you must race in such conditions, then you need to modify your behavior by going slower. This reduces your rate of energy expenditure and reduces the likelihood that you will overheat during exercise.

Finally understand that the most accurate measure of the efficacy of your drinking regime (other than your thirst) is provided by measuring changes in your blood osmolality (not in your body weight).

These are the guidelines that we advocate in most running and triathlon races in South Africa. Last Sunday approximately 9000 (I cannot find the exact number) athletes ran in the 56 mile Comrades Marathon in times ranging from 5hrs20 minutes to 12 hours in temperatures rising to about 26 degrees C. There was not one case of exercise-associated hyponatremia treated in the medical tent at the end of the race (even though there were 45 drinking tables on the course). A total of 150 athletes were treated in the medical tent, none was seriously ill and another 27 were treated in local hospitals with 8 still in hospital 12 hours later (diagnoses not known to me at this time). There were two deaths, neither related to abnormalities in fluid balance during exercise. I am not sure that this proves anything other than to show that it is possible to have athletes exercise for up to 12 hours without there being an epidemic of cases of exercise-associated hyponatremia (or the converse) simply by teaching them to "drink to thirst".

Glad to hear that someone with street cred concurs that Coggan is an egotistical blowhard!! Better put some ice on that, Andy...

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

"...because the Noakes views that i have read are directed to the care giver, medical director, etc.,"
- - So perhaps geared more to treatment rather than prevention?

"don't drink if you're not thirsty."
- - Which never worked for me. By the time I feel thirsty, it's too late to catch up.

"when i, who live in the high desert, have as my A race an event in kona. there must be more for the end user. therefore, i look forward to the answers and hope they come."
- - Opposite of the problem I had in Tucson which was caused by a tendency to sweat enough to keep my skin damp and in the desert dryness, I dessicated in record time. There is an acclimation that takes place to one's surroundings and an adaptation time or procedure that should be followed when going from one extreme to the other. I wish I had some clue as to what it is.

"you, dev, made mention of the adaptations you suspect your ancestors made to its exceptionally humid clime, and this (you think) caused you to react differently than would, perhaps, i. were i to follow the prehistoric DNA argument, i must assume my mojave desert (where i live) diet should consist of acorn mash, pine nuts, and the fly larvae lining the bottom of mono lake. if my stomach can't withstand native american diets (it can't), and the native american can't be healthy eating as a european does (he can't), is it appropriate to assume digestive systems have changed but all-things-hydration have not? i'm not using this to argue against the Noakes protocols for hydration, i'm just not a huge fan of basing medical advice on how my ancestors survived 1 million years ago."
- - 1 million years ago, of course not, but in Dev's case we're only talking two generations or so. Whatever genetic tendencies exist, I would expect them to become less operable as generations pass, and even less operable as an individual acclimates to new surroundings.

One can acclimate (somewhat) to hot or cold climates simply by living in them year round - my eighth winter in Chicago was much easier to bear than my first. And yet after only a year back in CA, I was totally de-acclimated, indicating that perhaps I was back to something that was more natural for me (because I was raised in CA or because my people came from a climate less harsh that Chicago). And perhaps my adaptation to Chicago's winters was eased because my "people" come from colder climates (than CA) in the UK, or because recent generations came from eastern Ohio and Western PA.

Not claiming I have the answers, or even th questions, just sharing some thoughts.

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Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

"1. Is salt intake necessary during prolonged exercise like the Ironman. "

thank you for your detailed and thoughtful response. i have been an ardent competitive runner for about 40 years, and what you write parallels my personal experience. of course that means nothing to most people, nor should it, but my instincts and sense of appropriateness have served me well in the main.

there is one area on which you touched, and on which you spent the most time in your response to me, that i believe may prove to surprise you (when all the ballots are counted). you're leaving the door open on the issue of sodium ingestion, i note. but you also seem to lean toward the view that salt intake is either not needed, or at least is not needed in amounts that exceed those found in your typical sports drink, and that salt, like water, is best ingested only when your body senses the need and apprises you of it through an urge.

you rightly point out that carbohydrate ingestion is much more key, and as i recall this is the one point of intersection between you and your contemporary, dr. coggan. perhaps my memory fails me, but i seem to remember that both you (on the one hand) and andy (perhaps along with ed coyle) both publish on this topic.

as regards sodium, what we see in sport is that the very best athletes swallow salt pills like they're gummy bears, up to and beyond 500mg/hr. this is in addition to whatever salt they might take in through other means (fluid replacement drink, gels, whatever). this raises a series of questions:

1. in a vastly different time and place long forgotten, i seem to remember the issue of osmolality broached not simply with respect to blood serum, but with respect to the ingested beverage. my pentagenarian memory may be conjuring up a parallel universe where biochemistry follows different rules, but i seem to remember the wish to avoid an over-high beverage osmolality, the cause of which was a too-high salt content. these hypertonic solutions presaged, as i remember, diminished gastric uptake. perhaps what i write reflects old science, and in fact hypertonicity does not represent an aborption issue. but for lack of a better term (i'm going to make up my own), let's call it "gastric osmolality," representative of a hypertonic "soup" sitting in your stomach. my question is whether this is an issue or not. if so, then i wonder how these guys can pop all these salt pills and still have gastric systems that absorb. if hypertonicity is not a problem, then i have my answer as to how you can pop salt pills like candy.

2. you write about the body's intent to protect its serum osmolality and, to that end, to resort to salt in its unionized form. you also note the body's ability to protect its serum osmolality. does a stable serum osmolality translate to a requisite number and variety of cations volunteering for their neuromuscular duties? in other words, is serum osmolality protection proof of, or in lieu of, the presence of electrolytes at the neuromuscular level?

i ask this because i can't get past the fact that a fair number of the top ironman athletes resort to the use of salt tablets. one would think that this sort of habit would have an effect. if you took one tab of LSD per racing hour during an ironman, something is going to happen to you. you might DNF, or you might win. but your body is going to have an opinion. likewise, this just seems to me to be too much salt intake for your body to ignore. i would think the body would express itself on the issue of 500mg per racing hour.

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Dan Empfield
aka Slowman

Hmm some great discussion here and perhaps the biggest bitch slap on ST ever...

Anyway, I seem to have a problem where I am cramping up in races. I am diabetic and quite often when I cramp up I am also high in blood sugar (from adrenaline, racing affects my blood sugar quite differently to training it seems). Being high in blood sugar makes me thirsty and makes you feel quite dehydrated. Usually the day before a race I find myself wanting to piss lots for some reason (and I do..), even though my blood sugar levels are normal and my fluid intake has not really changed. Same on the morning of a race...nerves or something?

Since there has been some great discussion on here, does anyone have any suggestions as to how to prevent these cramps? It has affected me (once real bad, entire lower body cramp) in my last 3 big races (one ironman race, one 2/3 half ironman (ie nz im 2006), and an olympic distance race). All of these races I have had quite high blood sugar whilst cramping it seems and I have also found myself wanting to piss lots the day before despite blood sugar levels being normal and fluid intake staying the same.

I used to get cramp at night when I was younger and would get cramp in my foot quite often when I was a swimmer.


ps am reeally working on the racing blood sugar thing.

It's really, really refreshing to hear your take on this. I have gotten totally sick of hearing people give me shit because I don't drink enough and don't take salt tabs. I just did IMCdA on no more than 60 ounces of fluid on the bike (more on the run because it was hot and I was more thirsty) and I finished the race feeling great. Everytime I have tried to drink more in training I ended up swollen, miserable, and dizzy. I don't doubt that many people need a lot more fluid than others, but the human body is pretty well adapted to tell us when we need more water. Thirst is a beautiful thing.

The salt thing is really interesting. So many people SWEAR by it. I can't even use endurance formula gatorade if it's not hot out or I retain water for 24 hours post training. It's amazing how differently people regulate sodium. I'd love to read more about it if you have some references!

:-)

Jodi

"some great discussion here and perhaps the biggest bitch slap on ST ever..."

yes, great discussion, but i would like to mention something about the world wrestling federation element to this thread. yes, andy coggan can be a world class SOB. he's also a world class scientist, and he is the consensus expert in one important element of cycling (training and racing with power).

he is also, as i recall, fairly heavily invested in research on gastric uptake. perhaps it's more along the lines of carbohydrate uptake during exercise, but that seems to me a pretty close cousin to the study of electrolyte balance, serum osmolality, hypervolemia and hyponatremia. carbohydrate uptake has nothing to do with hyponatremia, but both these scientists look at what happens to the stuff you put in your gut during endurance exercise, and how that affects your health and your performance. as such, coggan (who, along with noakes, holds a PhD) is every bit the qualified peer to comment on noakes' work and his views.

furthermore, philbert may not be entirely right in referring to noakes' message as evangelical, there is an element of that in play. one cannot blame dr. noakes for wanting to express his views on an impactful issue of broad relevance, and he's got a rare talent (among researchers) for translating them into a usable protocol at endurance events. lord knows, i'm guilty as charged if one has a problem with converting conclusions based on evidence to systems employed at the user level.

i completely understand if dr. noakes wants to take issue with the tone, or the terminology, expressed in this thread by andy coggan, philbert, or by me. but it would be wrong to say that andy stands alone in his disagreements with noakes (he doesn't) and it would equally wrong to think that andy does not have the bona fides to express his reservations. once we get past the question of how these reservations are written -- the expression of civility or the lack thereof -- we are left with whether you ought to drink more or less during exercise, and what ought to be in that water bottle of yours. i think that's what you want to find out, i know that's the case with me.

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Dan Empfield
aka Slowman

would be great if noakes or coggan could help me with my problem! :)

A great big thanks to Slowman and Noakes for such a great discussion. A few additional random points:

1. I find it hard to believe that race performance can be optimized in one who has lost up to 10% body weight.

2. My guess is that we are desensitized to the feeling of thirst. In our society where we drink way more water than we need and pee clear a few times a day, I'm just not sure my body really knows what "thirsty" feels like.

3. The feeling of nausea and decreased gastric emptying that may occur late in a race even when dehydrated might override the feeling of thirst/desire for fluids.

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Coach at KonaCoach Multisport

As a medical doctor, I may not slander a colleague without risking censure. The reason is obvious. Patients choose doctors on the basis of many factors including what they hear about that person. If the public is to be allowed to make decision based on reasonable evidence they must be protected from those (rogue) doctors whose personal agenda requires that they undermine the professional standing of certain colleagues (whom they usually find threatening for one or other reason).

Now I assume that the same probably applies to most professionals. Would an actuary for example like to read on the internet that his professional opinion should be considered suspect because he is only involved in that profession for reasons (including egoism and a lack of altruism etc) that must impact on his ability to function effectively in that profession? My point perhaps is that if the exercise sciences wants to be recognised as a real profession, then its practitioners should act with the ethical decorum appropriate for membership of a valued profession.

I am extremely comfortable to have my ideas challenged. But please present the contrary data so that we can talk about it in an unemotive, mature way. Don't publish claims that are simply wrong and would never stand up in a court of law. The one that really irritates me is to the effect that I ignore the data that disagrees with my ideas. In fact all my contrarian ideas come from a very deep investigation and understanding of the literature which then reveals information that is incompatible with the prevailing dogmas. Rather than continuing to teach and procreate those dogmas (the greatest sin of the teacher or scientist), I then present the evidence that leads me to conclude that the dogma is wrong and then embark on a research program to see whether or not the dogma can be falsified. Much of the evidence for this approach can be found in Lore of Running. Of course those who believe in dogmas may be scared of attempts to falsify them and can find this approach threatening. If an entire industry is based on one such dogma, then a case of mass anxiety and population-wide hysteria can develop.

In The Lucifer Effect, author Philip Zimbardo, the lead researcher of the infamous Stanford Prison Experiment of 1971 (http://www.prisonexperiment.org) details the danger of casting someone as "other" and hence not deserving of our human respect. Without mutual respect, science (like other activities) loses its potential to improve the human condition.

I would just like to say thank you for your posts. This has to be the single most helpful article (for me) ever written on slowtwitch. Keep up the good work.

"Now I assume that the same probably applies to most professionals."

i understand completely what you say. the push-pull here is that i publish a forum board, and the nature of this sort of environment is that my finger must be light on the "delete" button, or else those on this medium feel their views are censored. accordingly, i tend to allow a style of debate in which i might not engage. were i editing journal of applied physiology, that would be one thing. alas, they have not offered me that job.

conversely, if it's triathlon performance you're interested in knowing about, you might not have half a dozen current and former world champions piping up on JAP, as you do here. you just have to be ready to live in the wild west on this and most other internet forum boards.

we have quite a few very distinguished folks posting here, you among them, and i'm very glad you've added your voice. speaking selfishingly now, i'm quite eager to hear anything you might want to say about my questions re salt intake, and whether the body protecting its serum osmolality might be at the expense of performance in a long, hot race.

i might add that i've also heard from a medical doctor -- also phd, and practicing triathlete, whose career has been as clinical director for a variety of big pharma -- that he feels that the presence of salt on one's clothes may indicate the need for a lot of salt during a long hot race, and is probably indicative of a high salt diet. i wonder if these folks are in more peril of hyponatremia of their beverage/food intake is decidedly hypotonic.

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Dan Empfield
aka Slowman

All good stuff Dr. Noakes, but I have to get back to what Dan was asking earlier about the salt thing..I was a pro for 15 years, and for a lot of that time, we didn't know about salt, and a lot of us had problems. Once it became widely avaiable, somewhere in the late 80's, people started gobbling them down, and improving performance in heat related races. And today I'm watching the latest crop of pros take as many as 40 to 50 tabs during an ultra, amounts that are consistent with the pros of the 80's and 90's, and having no ill effects. Quite the contrary, most feel that it is allowing them to race longer in the heat. I know when I'm all cramped up and do nothing but drink after a race, it takes hours and hours before the cramps subside. If I load a bunch of salt pills, then the cramping time is measured in minutes rather than hours. I've had my blood tested, and the sodium levels are dangerously low after a hot race. For some reason my body does not conserve as many do, and I believe it is one of the contributiors to my heart damage over the years. I know I'm just one person, but if I'm this way, then others must also be. I have no doubt that you studies show what they do, I'm just not comfortable with any broad brushes being painted when it comes to hydration and mineral supplemantion. I'm not saying that is what you are doing, but like Dan, I would like to hear your thoughts on the pros that have been regularly taking massive amounts of salt over the years.....ANd I'm talking about ultra events, I concede that 2hour+ marathoners don't require much of anything. I can go two hours all out myself with a couple sips of water, and race to my potential.....

To return to the salt issue, let us work out what is the potential effect of ingesting 500mg of salt per hour (ie approximately 200mg sodium. Note that 1 mmol of sodium equals 23 mg). This is still quite a small amount and probably less than they are losing in sweat (if they are exercising at a sweat rate of about 1000ml per hour which seems a reasonable sweat rate for a majority of more competitive Ironman triathletes). Current methods of sweat collection probably overestimate true sweat sodium concentrations which might be between 20-40mmol per litre in well conditioned athletes. This gives an hourly sweat sodium loss of up to 450-900mg rather more than the amount being ingested. However drinking a sports drink might add another 200-400mg per hour. Thus if the concept is that athletes must replace all their sodium losses during exercise, it would seem that one might need to ingest more than a single sodium tablet each hour during exercise.

With regard to the question of the drink osmolality and the effects on gastric emptying, this is clearly an issue. However if the tablets escape digestion until they are out of the stomach, then this is not an issue. Adding a single 500mg sodium chloride to a drink will, according to my calculations, increase the osmolality of the stomach by 15.5 mosmoles per litre (equivalent to 30mosmoles per litre if you are drinking 500ml per hour). This does not seem to be a great issue since adding 60 grams of glucose (the amount of carbohydrate that we suggest Ironman triathletes should ingest each hour) will increase the osmolality of the drink by 330 mosmoles/litre. This is a hypertonic solution. Ingesting a longer chain carbohydrate will reduce this osmolality effect for as long as the carbohydrate remains undigested which is probably not too long in the human stomach and intestine. Perhaps the point is that, according to these calculations and assuming they are correct, the effect of ingested carbohydrate on the osmolality of the fluid in the stomach is probably much greater than the effects of the relatively small amounts of sodium that are ingested. I suspect that athletes adapt to what they drink and that their gastric emptying might improve with the practice of ingesting fluids and eating foods that cause their stomach osmolalities to be rather higher than we might expect.

With regard to the issue of osmolality protection, you need to remember that the principal design feature of the human body is not to produce feats of great athletic endeavour (although it turned out that being able to run in the heat became an important determinant of how we evolved). In other words we are not designed simply to travel between two geographical points on the island of Kona (and elsewhere) as fast as possible. Rather the priniciple focus of our design is to protect our brains from damage - that is my interpretation. So the brain protects the body osmolality because, if it does not, then the brain cells will die either because they become dessicated by too high an osmolality or waterlogged by too low an osmolality. During exercise the brain does this by altering our behaviors in order to protect itself. So if the osmolality changes in a way the brain does not like, it will signal that you should drink more, or perhaps ingest more salt or perhaps you should slow down or even stop exercising. The effects of changes in osmolality on the muscles and the neuromuscular system (other than the brain) probably only occur when the osmolality has gone well out of the range that the brain will allow under normal conditions when fluids and electrolytes are appropriately available. The times that the brain has trouble regulating the osmolality is when we are stranded in the desert without any fluids or when we drink more than we should because we have been programmed to over-ride the normal brain controls of drinking according to thirst or when we have kidney failure (amongst a few other causes).

Finally there is now good evidence that, at least in short duration exercise, the ingestion of carbohydrate does not act by altering metabolism in any significant way. Rather it probably acts by indicating to the brain that the body is going to be fed during the exercise so that a higher exercise intensity is allowable (by the brain). The sensory receptors for this effect probably lie in the mouth or throat. Perhaps salt ingestion might act in the same way.

What you believe determines what you believe. If you believe that ingesting these rather small amounts of salt improve your performance, then it is probable that they will. But the more probable mechanism is in the brain rather than in the muscles. (Please note that this is a personal hypothesis - it is not a PROVEN FACT).

But be warned that the over-ingestion of salt can be dangerous. A competitor in a recent Race Across America presented to the medical staff after he completed a few days of the race. He had fluid on his lungs (pulmonary edema) and had to stop exercising. He had heard that salt ingestion was good for performance. So he had taken 23 grams of salt each day together with a generous fluid intake. This had expanded his body water content to the point where the membranes of his lungs began to leak fluid leading to his pulmonary edema. Interestingly his tissue osmolality was not affected (since he had retained the sodium) so his brain did not swell as it would have if he had only ingested too much fluid and developed hyponatremia which would have stopped him by causing him to become confused and eventually lapsing into unconsciousness.

MOre great stuff here, but the sodium intakes I was talking about are in the range of 800 to 1000mg per hour...That is what a lot of pros used to do, and are doing today..I always suspected that if taken in pill form, that it wouldn't upset the stomach osmality so much..I used to think why not just put the salt pills in my water bottles, saves the hassle of popping pills while riding. Just assumed that they all go to the same place, but I remember having trouble when I did that, vs just taking the pills..ANd many are coated these days, or in capsules, so makes sense that they might travel farther along before they dissolve, and thus not raise the sodium levels so much in the stomach..

I see your point as to the race across america guy, but perhaps he was taking sodium without knowing if he really needed it in the first place, and thus over such a long period, overdosed. I've taken that much over longer period of times, and had no problems at all.....Of course I don't retain sodium very well at all......

Hopefully I answered your question in my previous post to Slowman.

The danger with anecdotes (which I always take very seriously) is that they are not objective. As I said - what you believe determines what you believe. Your explanation indicates that you believe that you can become hyponatremic by sweating out too much salt and by not taking in enough to replace those losses. This may be so but it has never been shown scientifically. Rather all cases of serious hyponatremia (confusion; convulsions; pulmonary edema; death) occur in those who ingest too much during exercise and who show no evidence for excessively large sodium losses (ie greater than those who finish these races without hyponatremia).

You also believe that salt loss causes muscle cramps since by ingesting salt after races you recover so much quicker. Again there is no scientific evidence that salt loss has anything to do with muscle cramps - which does not mean that this is not the case, just that when we look for the evidence in scientifically controlled studies, we don't find any evidence for this relationship. Then there is the question of the placebo effect of taking something when you are ill and the beneficial effect of believing that the substance will have an effect. The only way you can disprove the placebo theory is by ingesting active and inactive substances without knowing which is which. If the active ingredient (in this case, salt) is more effective than the inactive placebo, then there is scientific evidence for the hypothesis.

To begin to develop an hypothesis from anecdotal observations we need first to collect the relevant data. An obvious experiment to begin to address this question would be to do a prospective study of the outcomes of athletes who do and who do not ingest additional salt during very prolonged exercise. If the salt ingesters do indeed have fewer cramps and finish quicker in this analysis, then one can undertake a placebo-controlled, randomized trial of salt ingestion in the Ironman. We did this some years ago and did not find that there was any effect on blood sodium concentrations. But the study was too small (few funds for these studies) we did not really study performance or the effect on muscle cramps. However my colleague Prof Martin Schwellnus has recently completed a prospective study of muscle cramps in the 2007 South African Ironman - the largest study yet completed - and he has some interesting findings which do not support the salt depletion theory. But I cannot say more until the study is peer-reviewed and published in the scientific literature.

I agree that anecdotes are not the end of a discussion. But the ones that do not have axes to grind(sponsors, companies with a financial stake, ect.), should be looked at serioulsy..How many times have professional athletes shown something to be true, in the face of science that counterdicted them earlier on?? I have found that science in my career, has always been a little behind the pro curve. Once science recognizes that something is happening in all those anecdotes, they then set out to prove why it is so, or different from what they earlier believed. As you yourself have said, you have changed your mind over the years about this topic...

As I said earlier, I have done lots of blood tests during my training and racing, and I will have severly low blood sodium and magnesium levels if I don't supplement. SO unless my blood is susceptable to the placebo effect, I need another explination for what's going on in my body.....Thanks again

Dr. Noakes, a few additonal questions if I may:

You mentioned several signs of excessive hydration to look for during a race. In your experience, how dependable are these signs? How specific are they? Have you known athletes who noticed such signs and were then able to avoid a catastrophic outcome? Do you have any feel when these signs begin to develop, i.e. at what weight gain level or sodium level?

You addressed the issue of weighing oneself during a race, stating that the body defends itself against change in osmolality rather than weight. However, osmolality can't be assessed on course. Weight is one of the few objective factors that can be assessed during an event. Do you think one could be significantly misled by knowing this information assuming it's accurate?

My feel is that few would dispute relying on thirst to avoid hyponatremia, and while this is the more important issue from a life/death standpoint, optimizing race performance is also of importance. You mentioned your own experience as well as that of Kenyans being able to perform at a high level despite significant weight loss, even in excess of 5% body weight. But these efforts are in the 2-3 hour range, not the 8-11 range we see in IM racing. Do you have any data regarding weight loss of IM triathletes and its effect on performance?

You've made no mention of exercised induced SIADH on this forum, but have rather taken the stance that people are simply overdrinking. Do you think it plays a role?

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Coach at KonaCoach Multisport

If taking 1000mg per hour is helpful, it will be very difficult to study scientifically since I doubt that naive athletes would be prepared to do this as part of an experiment. When we did such a study the subjects voluntarily chose to take in much less salt. This suggested to us that there is little drive to ingest additional sodium in naive subjects during an Ironman - ie there is no development of a salt craving during such exercise .

Interestingly salt at this dosage (note that the daily requirement in non-exercisers is about 1-2 grams) may act in a quite different way than we might expect. There are salt sensitive and salt insensitive subjects and the difference may be in the way their autonomic nervous system responds to salt intake. I am not an expert on this topic but it is possible that a salt sensitive person taking large amounts of salt might enhance his or her performance as a result of changes in hormonal balance, activation of the sympathetic nervous system etc that has nothing to do with regulating the blood sodium concentration. At such high doses salt might act in quite different ways than in the range of more normal intakes.

Great post Dev. Glad your still with us :)

I truly appreciate what you are saying.

In South East Asia though , it is so damn hot and thirst feels very real.

What you have learnt and lived to tell is so valuable.

I use INFINITT and supplement with gels and Endurolytes. I have made numerous posts with regard to my thoughts on electrolytes and water useage whilst training and more importantly racing. It is a long process , six years so far and I still haven't mastered it.

Thank you for your post.

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"You are never too old to set another goal or to dream a new dream" - Les Brown
"Discipline is the bridge between goals and accomplishment" - Jim Rohn

This is a good discussion to bring back now that racing season is upon us.

Well now that you bothered to dredge it up, I took the time to re-read it, and I have to say, the comments of certain parties contain so many mis-statement and mis-attributions as to be comical. So as to not fan the flames, I'll leave it at that, but any one who reads this thread should be aware of that fact.

I haven't read it yet, but your post seems to indicate Frank Day is quoted several times...

;)

Then, we agree that the ideas should probably be revisited?

I was at a conference in Boston a couple of weeks ago, and, indeed it appears that the muscle injury induced release of arginine vasopressin, and thus this is really an SIADH issue. With euhydration everything is OK, but overconsumption of water in the face of the AVP is the culprit.

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_________________
Dick

Take everything I say with a grain of salt. I know nothing.

Hello Trifan and All,

I have a speed display, powermeter, a heartrate monitor, cadence monitor (running and bicycle), altitude monitor, time indication, and so on.

None are necessary to train or race.

Using percieved effort (the Super Compter) can be adequate (and some say better) utilized to run a race. (a heck of a lot cheaper too)

But I like having the information and adjust my effort according to that information (and percieved effort).

Having my weight displayed at the turnaround on the run and at about 2 miles before the finish would be interesting to me.

Trucks can be weighed on the fly. Runners could be weighed on the fly too.

Trucking companies can equip their trucks with transponders that identify them as they approach 21 Oregon weigh stations located around the state. The stations are equipped with the Green Light weigh station preclearance system that can weigh trucks in-motion at highway speed and signal them to proceed without stopping if they pass an instantaneous check of size, weight, height, registration, road-use tax account status, and safety records. Transponders are palm-size devices that are affixed to the inside of the truck windshield. They're available at no charge for trucks that have permanent Oregon registration credentials, three axles or more, and a minimum declared weight of 34,001 pounds. The truck must have been stopping at Oregon Green Light weigh stations an average of at least once per month. Also, the company may not have an "Unsatisfactory" safety fitness rating.

Runners would be weighed as they run across a mat (like reading the chip) and the results displayed on a small billboard just like the traffic speed reading devices.

While weight is not a measurment of serum sodium it could be helpful if you see yourself gaining weight during the race.

For more fun - the runner's pace could be displayed also. (realizing that they had just speeded up a bit to get a faster reading)

The elites weight and speed information would be interesting data for TV fans. (along with their currently displayed bike SRM readings.)

It would be up to each athlete as to how they used the information in regard to whether they are drinking too much or too little. (for the thirst and salt sensing deficient runners)



And the system would provide another profit center for the chip timing industry.

When the BMI police take over the weighing mat could be deployed on city sidewalks to improve the health of the nation.

What do you think?

Cheers,

Neal

Do you suppose the Tanita scale could be modified to show serum sodium levels?

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Cheers, Neal

+1 mph Faster

I didn't read the article but I had this problem before I quit our local Hash House Harriers club.

This thread was recently brought to my attention. Let's just say that I found it...illuminating.

Great article.

I used to work with a group of patients from a large Psychiatric Institution. My six had the diagnosis of 'radiator syndrome' because you could generally find them stretched out over a warm radiator; a response from being hypothermic.

The article about drinking too much and it's effects really reminded me of my six since they all had the particular behavior of 'drinking way too much'. My six would get absolutely 'drunk as a skunk' on H2O if they had any access, then shiver like crazy from a belly full of coldness. We used a weight scale Q1h to try and determine if anyone snuck a drink - as this information determined the metered doses of fluid for the rest of the day. Hyponatremia in these patients was taken very seriously. Sadly, all had terrible sounding hearts, major GI disorders and rather short life-spans.

Truth is...once hyponatremia set in, these folks could barely walk - let alone run. All we could do at this point was to cut them off AA style and monitor for a couple of hours until the symptoms subsided. When I say 'cut off' I mean the Dr's orders were 'nothing by mouth' until they could pass a sobriety test.

Thermo