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Article on drinking too much during exercise
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Interesting article on overhydration and endurance sports.

http://news.yahoo.com/...dlywaterintoxication
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Re: Article on drinking too much during exercise [trifan] [ In reply to ]
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overhydration or too little sodium you make the call :)
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Re: Article on drinking too much during exercise [trifan] [ In reply to ]
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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 ;-)

Dan Empfield
aka Slowman
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Re: Article on drinking too much during exercise [RBR] [ In reply to ]
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Quote:
overhydration or too little sodium you make the call :)


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

Dr. Philip Skiba
PhysFarm Training Systems
Coaching, Consulting and Technology for World Champions, and You.
Dr. Phil's Books available here
Last edited by: Philbert: Jun 19, 07 15:28
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Re: Article on drinking too much during exercise [Slowman] [ In reply to ]
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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.”








"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."
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Re: Article on drinking too much during exercise [Slowman] [ In reply to ]
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Quote:
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 ;-)
Huh?

Dr. Philip Skiba
PhysFarm Training Systems
Coaching, Consulting and Technology for World Champions, and You.
Dr. Phil's Books available here
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Re: Article on drinking too much during exercise [Philbert] [ In reply to ]
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In Reply To:
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overhydration or too little sodium you make the call :)


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

If I'm remember right, both those studies where done with fluid loading at rest, not exactly a real world test.
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Re: Article on drinking too much during exercise [indytri] [ In reply to ]
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There are fairly consistent observational studies from IM and marathon events demonstrating that weight LOSS is associated with no hyponatremia and faster finishing times.
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Re: Article on drinking too much during exercise [indytri] [ In reply to ]
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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".

Dr. Philip Skiba
PhysFarm Training Systems
Coaching, Consulting and Technology for World Champions, and You.
Dr. Phil's Books available here
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Re: Article on drinking too much during exercise [Philbert] [ In reply to ]
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"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?


Dan Empfield
aka Slowman
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Re: Article on drinking too much during exercise [Slowman] [ In reply to ]
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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?

Just Triing
Liking ST more since finding the block user post option.
Triathlete since 9:56:39 AM EST Aug 20, 2006.
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Re: Article on drinking too much during exercise [trifan] [ In reply to ]
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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"

___________________________________________
Ego numquam pronuncio mendacium,
sed sum homo salvaticus
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Re: Article on drinking too much during exercise [DavHamm] [ In reply to ]
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"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?


Dan Empfield
aka Slowman
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Re: Article on drinking too much during exercise [Slowman] [ In reply to ]
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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

Dr. Philip Skiba
PhysFarm Training Systems
Coaching, Consulting and Technology for World Champions, and You.
Dr. Phil's Books available here
Last edited by: Philbert: Jun 19, 07 17:57
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Re: Article on drinking too much during exercise [Philbert] [ In reply to ]
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"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?


Dan Empfield
aka Slowman
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Re: Article on drinking too much during exercise [Slowman] [ In reply to ]
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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.
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Re: Article on drinking too much during exercise [trifan] [ In reply to ]
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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.
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Re: Article on drinking too much during exercise [Slowman] [ In reply to ]
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hat'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?

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

Dr. Philip Skiba
PhysFarm Training Systems
Coaching, Consulting and Technology for World Champions, and You.
Dr. Phil's Books available here
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Re: Article on drinking too much during exercise [MPB1950] [ In reply to ]
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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
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Re: Article on drinking too much during exercise [Philbert] [ In reply to ]
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"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.


Dan Empfield
aka Slowman
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Re: Article on drinking too much during exercise [Slowman] [ In reply to ]
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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.
Last edited by: dkv: Jun 20, 07 4:02
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Re: Article on drinking too much during exercise [Slowman] [ In reply to ]
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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

Dr. Philip Skiba
PhysFarm Training Systems
Coaching, Consulting and Technology for World Champions, and You.
Dr. Phil's Books available here
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Re: Article on drinking too much during exercise [dkv] [ In reply to ]
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"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.


Dan Empfield
aka Slowman
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Re: Article on drinking too much during exercise [Slowman] [ In reply to ]
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In Reply To:
"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

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).
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Re: Article on drinking too much during exercise [Slowman] [ In reply to ]
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"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?
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.
Last edited by: Andrew Coggan: Jun 20, 07 7:04
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