To what study or studies are you referring?

Regarding cramping: I had some pretty serious cramping at the end of a long rugby practice back in the '90s. Later, I discussed that with a girl who was working as an athletic trainer at the time. She asked me, "Are you drinking milk?" I said, "No, not at all." (At that point, I wasn't drinking any.) She told me then it was likely related to a calcium deficiency.

I started drinking milk again, and I haven't had cramps since.

I had the same discussion with a marathoner (my dad) a few years ago: "I had this awful cramping around mile 20." "Are you drinking milk?" "Not at all." "Maybe you should."

So, Dr Noakes, or anyone else who wants to respond, is calcium deficiency perhaps a more primary cause of cramping? How about other electrolytes like potassium? What's their relationship to all of this?

So you don't think that observational studies in the field are the best way to answer such questions?

Dan,
At a recent fund-raiser 5k in Glendale, I met a duathlete who is proficient enough to have been to the world champs and he said that any sodium intake by him during races makes him nauseous. I, on the otherhand, do the opposite. I get nauseous and feel drained on hard efforts over an hour without a salty fluid. When I played tennis in my teens, in El Paso, we did pretty well with just water, but I did begin to bloated and sluggish after a few hours. I always went home after a few hours of playing with big white lines all over my body. (the dog loved it.)

As an undergraduate in New Orleans, where sweating took on a whole new meaning, after a set or two, even with plenty of water I felt very sluggish and bloated. A playing partner introduced my to Gatorade. This was in the 70's, and, if I recall correctly, the formula was closer to Pedialyte (2.5% glucose and ~0.3Normal Saline--less sugar and more sodium. It also tasted pretty lousy). After that, I could down a quart after each set and play for much longer period without losing performance.

When using cytomax, I just couldn't get over the bloated feeling and nausea until I began to add salt to make a mixture of around 25mg/oz of fluid. So, this is proportion that I use, except of shorter workouts, where water seems to suffice.

I suspect that some individual variation is at work here and might explain why some athletes, like the duathlete above and Fleck (if I recall correctly) do not use or like sodium in races and others don't seem to do well without it. Maybe those of us needing more have ancestors that evolved in areas where the was no shortage of sodium and others in more inland valleys and highlands where sodium is less available. Or, we are just 'weak sauce.'

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_________________
Dick

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

... a sexual disparity could be explained from an evolutionary standpoint if we assume that males were more likely ...

fine. except that there really isn't a lot of compelling evidence for gender-based roles in early human or pre-human populations. so maybe we could just skip the usual hand waving "men hunted, women raised children" simplifications, and move right along?

No, because you are only seeing the end result and you don't know if there is one or several mechanisms that might lead to a similar end. And, it is difficult to do the specialized testing necessary to understand what is going where.

Not every person has this problem. Unless you understand the characteristics of those who do and what it requires to avoid such problems in those people you cannot say you understand the problem. If we could figure this out from simple "observational studies in the field" this would have been solved a long time ago as this issue has been around and observed by many very smart people for a long time.

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Frank,
An original Ironman and the Inventor of PowerCranks

It makes perfect sense that performance could be maximized with a slightly smaller than resting ECF volume, since this reduces the diffusion distance of oxygen from the capillary to the mitochondria, at least as long as enough blood volume is maintained to maintain cardiac filling pressures to maintain cardiac output.

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Frank,
An original Ironman and the Inventor of PowerCranks

If it makes you happy, but it's funny how many primitive societies still follow this pattern. It also seems funny that gross uniformity of activity & environment appears to be what drives adaptation & evolution but if you want to think the women hunted and the men stayed back and did their nails power to you.

JJ

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Every night that I run, the thought crosses my mind that there's no way in hell I'll still be running a month from now.

thank you for taking the time to comprehensively confront this for us.

your explanation notwithstanding, i am still left with the question of what causes my muscle cramps. further, i also suffer from an occasional heart arrhythmia at moderately high heart rates, specifically a-fib above HRs of 135 or 140 bpm. this is short lived, just 3 or 4 beats at a time, and self-resolves, but it seems persistent after several days of intensive training, esp if a large component of that training is high-HR.

i can only guess at the mechanisms, but since both heart function and muscle contraction are electrical functions, i'm left to wonder whether it's a cation i'm low on.

as frank day pointed out, while sodium stores (except for the hidden sodium treasure) are readily measurable because the cells' active pumping of sodium into the ECF, potassium exists largely in the ICF and is therefore hard to measure. i'm quite eager to hear that my problem is not with sodium, but with K+, Ca+, Mg+.

that established, i'm still not convinced that Na+ supplementation is a bad thing. let's liken it to petroleum. what you're saying is that the body maintains the sodium analog of what in america is called our "strategic petroleum reserve," which for lack of a better term consists of a "valve" our government turns on and off to moderate the effects of acute petroleum shortages. if the body, during exercise, excretes large amounts of sodium through sweat, and calls on its "strategic sodium reserve," then that sodium will have to be replenished eventually anyway. why not during the race instead of after the race?

but let's leave that aside. to bottom-line it, i'm guessing (and it's just a guess) that my a-fib and my cramping might have etiologies in some way connected. i don't personally care whether gatorade makes billions or goes broke. if all my muscles (heart and skeletal) rhythmically fire, i'm a happy guy. i'm open to hearing that it's not due to a lack of Na+, but what about the other cations? my occasional exercise-induced a-fib is nothing compared to heart problems associated with hyperkalaemia, and i don't know when and if i might be in danger of intaking too much potassium.

if i was to hazard a guess, it would be that my Mg+ is the one cation i might be missing, only because of my occasional and stress-induced arrhythmia. but my cardiologist is so busy shuffling 85 year olds in and out of his office he's got no time for a thoughtful discussion.

whether it's on this thread or elsewhere, i would eventually like to drill down to:

1. what relieves or delays cramping?
2. what bad thing can happen if i take salt pills during a race, during a workout, after a workout, assuming i'm not hypertensive?
3. what do we do with the very high incidence of salt pills taken by top triathletes? are they all indulging in mass cation hysteria?
4. and finally, anecdotal cases of hyponatremia in my experience pale in contrast to anecdotal cases of heart arrhythmias in otherwise very healthy athletes; can prolongued exercise in the absence of a certain factor be the proximate cause?

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Dan Empfield
aka Slowman

Wendy Ingram spoke at a local Tri Club meeting a few years back and was asked about the "Crawl-Fest" in Kona. She said that she typically wore a pouch around her wrist to store her salt tabs and that she accidentally left the zipper open and lost all of the salt. She seemed certain that's what caused her meltdown.

Maybe that was the problem, maybe it was something else but it seems like "Wing Nut" paid very close attention to detail and her salt intake was the only element that was not executed accoring to her plan. Slowman noted some real-world experiences that seem to support his claims that taking on salt has helped him. At Oceanside this month, I felt a cramp coming on at Mile 1 of the run. I forgot my salt on my bike so I grabbed some pretzels and bananas at the first two aid stations. The cramp went away.

I guess my point is that while all that science looks impressive...and sorry, is as boring as whale shit...I think it's possible that something is missing. I think it goes without saying that everyone should experiment during training, figure out what works for them, and do that on race day.

1) "primitive" societies are human societies that are generally at least 5-10,000 years old. there is some evidence that they have undergone their own kinds of societal transformation during that time, and although they can serve as useful indicators of how very early humans may have lived, they are certainly not examples of very early human life.

2) early humans didn't hunt much anyway, so the notion that one set of them stayed home and did X while another group went out hunting appears (based on current archeology) to be a bit of a distortion.

3) if you take a look at non-human primate societies, which have also likely changed in significant ways since the fork that gave rise to us, you will find some gender based roles but they appear to have a lot more to do with mating and dominance behavior than with the kinds of physical tasks that might lead to gender disparities in relation to "endurance athletics". male, non-human primates simply do not spend much time doing things that would lead to to strong evolutionary benefits for those adapted to endurance tasks.

4) studies of both chimpanzee and orang-utan clans suggest that both males and females appreciate doing their nails to about the same extent.

5) anytime an animal lives in a predominantly social context, evolutionary pressures change dramatically. what leads to genetic continuance in even a small tribe of hunter-gatherers is very very different from the traits that lead to success as a lone predator. there are some hypotheses that suggest that traits like empathy (in the broadest sense of having some clue what another individual is thinking), communication (verbal, body, other) and planning are probably more critical to genetic continuance in even early human societies than the ability to run towards or away from potential food sources and predators. its not likely that we're going to know the relative significance of these kinds of traits for a very long time, if ever.

That is a huge presumption that large fluid losses during exercise are mostly accounted for my drops in ECF volume. I suspect that large fluid losses do not see large ECF volume losses because of the buffering effect from fluid shifts from the ICF just like large shifts in acids in the body do not cause large shifts in pH because of the buffering system in place. Unless these different compartment volumes are actually measured during these conditions one is just guessing as to what is going on.

Your arguments seem to imply that it doesn't matter how much fluid the athlete loses, they will be ok, perhaps even perform superiorly - as long as they "listen to their thirst". In my opinion, such an approach may work for some but will fail many.

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Frank,
An original Ironman and the Inventor of PowerCranks

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Every night that I run, the thought crosses my mind that there's no way in hell I'll still be running a month from now.

I suspect that some individual variation is at work here and might explain why some athletes, like the duathlete above and Fleck (if I recall correctly) do not use or like sodium in races and others don't seem to do well without it. \\

This is exactly right. And when you study certain groups of people, you very well may get a skewed result. If you only look at elite runners, you are looking at mostly super low body fat folks of mainly African descent. If you study Ironman champions, most have been pre selected for heat tolerance from their genetics. That is a big reason they are at the top of Hawaii, so to test them only would not be a fair sampling..

In Noakes talking about the house study, I don't doubt the results, but Ironman is not sitting in a house for days on end with no salt. What I think happens is a vastly accelerated version of the study. I feel that in a 9 hour race in Hawaii, it could quite possibly be like a week in that house, as far as depletion is concerned. And in that house, the body has time to regulate and compensate for the stress put on it. I believe in racing, the bodies compensation triggers, do not have time to click in so to speak, and thus cannot be relied on for good information. That is why almost all sucessful Ironman athletes stay ahead of those, and begin drinking, eating, and electrolyte supplements before the felt need for them.

Basically I'm with Frank on this(who would have thought? (-;, you need to study the entire situation, before, during, and after, and you need a representative sample group. I guarantee you that if you take me, Molina, Pigg, and a few others, and you just test us, then the result is going to be waaay different that if you take Paula, Dave, Chrissie, Erin Baker, and all the others that have done well at Hawaii, and seem impervious to the heat there....

Dev, I'm curious as to why no long runs after long flights. I'm doing more international travel these days (LA to Buenos Aires this week) and upon arrival in BA did an easy 10-mile run. Was this a mistake? I'd be curious what guidance GregX or others have provided in the past to lead you to not run long off the flight.

Thanks.

Fred

I am catching this thread a little late so please forgive me if these issues have been addressed. If I am reading your post correctly, you imply that we do not need to ingest sodium during a race because our bodies have internal stores of sodium and it makes sense that evolutionarily we have evolved to not need to take it in.
My question then is, do you suggest athletes not ingest calories? It seems to make sense given the logic on sodium. Our bodies have vast stores of calories which they can access during prolonged (multi-day) periods of calorie restriction/starvation. It also makes sense that evolutionarily we would evolve to be able to access these calorie stores. Bonking in a race is bad, bonking while being chased by a predator is death. Yet I hope you would not argue we do not need to consume calories in a race. Yes, we have vast stores of fat which could be used. However we can not access them as quickly as we are using them. Perhaps it is the same with sodium? Yes, it makes sense evolutionarily that we would have evolved to not need to take in calories. Perhaps evolution is not perfect. Perhaps the demands placed on our bodies during exercise are such that evolution has not been able to fully tweak these systems.
It makes sense that we can outrun our bodies ability to regulate itself. You make a comment about, "the belief that the body has no ability to homeostatically regulate its losses and so will just continue to exercise until there is a catastrophic failure of function, in this case muscle cramps." That is my believe. It makes sense our bodies evolved to be able to run until we die because exercise meant survival. You ran to eat or not be eaten. Anything which hindered your ability to run meant death. So yes, we can run to catastrophic failure. And evolution worked to try to put off this failure as long as possible. But it is not perfect.

Basic Physiology 3.

As presented by the Sports Drink Industry and its funded scientists and sports medicine and athletic coaching associations.

1. Humans are a divine creation with a biology that is unique and unrelated to that of all other creatures on earth.

Thus whereas all other creatures on earth are able to regulate their body temperatures and body water and sodium balance by responding to internal cues, all humans must be told exactly when, how much and what to eat and drink before, during and after exercise.

2. Because they are unique creatures, humans have no capacity to homeostatically-regulate their bodily functions particularly their body temperatures, their levels of dehydration and their body salt levels during exercise.

Instead when they exercise their body temperatures rise precipitously leading ultimately to heat stroke or “heat illness” or heat cramps; they develop “dangerous dehydration” causing heat stroke and “heat illness”; and they continue to sweat a “salty sweat” leading to salt-deficiency “heat illness”, salt-deficiency muscle cramps and salt-deficiency hyponatremia. Many of these conditions are potentially fatal.

As a result it is very dangerous for humans to exercise unless (i) they follow the cautionary guidelines provided by influential sports medicine and athletic coaching associations (many of which are generously supported by the sports drink industry to insure that all humans – at least those in the developed world who perhaps have a larger disposable income – appreciate these specific biological weaknesses) and (ii) they ingest novel products designed exclusively for their use and which provide exactly the right amounts of water, salt and other necessary ingredients to insure that they do not develop any of these catastrophic conditions during exercise.

3. Since all other creatures on earth are different, they do not need this information. Thus Veterinary Associations caring for all other creatures do not need to produce detailed guidelines advising dogs, cats, lions, camels, large antelope etc how much, when and what they need to drink before, during and after exercise. Since they have a different and much superior biology (perhaps designed by evolution) that accurately provides this information on a moment to moment basis, they do not need other dogs, cats, lions, camels, large antelope etc to form associations advising each separate species how much, when and what they need to drink before, during and after exercise.

4. There is no limit to the amount of fluid that can be absorbed by the human intestine. Thus a 50kg world-class runner able to sweat at a rate of 3L/hr has the capacity to replace all that fluid and must drink at a rate of 3L/hr (1L every 20 minutes).

5. Anyone who disagrees with any part of this analysis is by common consent an idiot and must be publicly humiliated at every opportunity (see the thread: Why can’t experts agree etc).

Comment: Surprisingly humans have had great difficulty deciding exactly how much and what athletes should drink before, during and after exercise. Before we knew better (ie before the development of the sports drink industry and its funded scientists who worked out 1 and 2 above) humans were advised NOT to drink at all during exercise but that they could ingest salt tablets. Water was considered anathema since it would cause a “stitch” and a sudden impairment in performance known as “weakness”.

Then almost out of nowhere in 1996 the industry-funded American College of Sports Medicine (ACSM) decreed that from now on it was only safe for humans to exercise if they drank either 600-1200ml per hour or “as much as tolerable” during exercise. The ingestion of sodium during exercise was also essential to prevent hyponatremia. Failure of humans to follow these guidelines precisely would cause all exercising humans to develop all the conditions described in 2 above. (This despite an absence of any evidence that these conditions had occurred commonly in athletes who had competed in athletic events including marathons and ultra-marathons between about 1880 and 1970 and had drunk little if at all during those competitions). A global pandemic of cases of exercise-associated hyponatremia (EAH) was unleashed when these guidelines were adopted.

In 2007 the ACSM significantly modified these guidelines which now state that athletes should drink according to the dictates of thirst but should not lose more than 2-3% of their body weight during exercise. Now appropriate fluid intake rates are between 400-800ml/hour. The ACSM continues to advise that sodium must be ingested during exercise in order to prevent EAH.

In contrast US Track and Field and the International Marathon Medical Directors Association have adopted guidelines which propose that the optimum drinking guideline is to drink to thirst regardless of the extent of weight loss that develops during exercise. These guidelines are based on the theory that the brain uses thirst to drive appropriate drinking behaviour and that if the athlete chooses to ignore thirst eventually the brain will cause the body to slow down until fluid is ingested so that the symptoms of thirst disappear. The guidelines do not propose that sodium needs to be ingested during exercise to prevent EAH.

The International Consensus Statement on EAH also agrees that sodium ingestion is not required to prevent EAH.

Basic Physiology 2.

Humans are designed to homeostatically-regulate with exquisite accuracy the amount of sodium that is present in their bodies. They do this by matching to the nearest few milligrams the amount of sodium that they ingest and lose each day. Without this exquisite regulation, human life would not be possible.

It is my argument (based on the work of Dr Dan Lieberman of Harvard University amongst many others) that we evolved as sweaty, long distance runners in a relatively salt-free environment and so evolved mechanisms that would allow us to exercise in heat whilst losing some salt in sweat but still maintaining whole body sodium balance even on this relatively salt-poor diet. I presented some of the evidence for this in the thread: Why can scientists never agree etc.

First is the evidence that it is extra-ordinarily difficult to produce a sodium deficit in free-living humans. In fact the condition may not exist in free-living humans. One of the only studies of which I am aware in which a true sodium deficit was produced was the study of McCance described in Basic Physiology 1. But this could only be produced by subjecting the subjects to Mrs McCance’s sodium-free diet and then forcing them to sweat heavily by exposing them to severe heat on a daily basis.

Second were the studies of iconic US physician JW Conn of the University of Michigan Medical School at Ann Arbor. He noticed that subjects undergoing a period of heat acclimatization reduced their sweat and urine sodium concentrations. He then wondered what causes this and what was the effect of reducing the amount of salt in the diet. He showed that almost immediately on exposure to a reduced sodium intake subjects reduced the amount of sodium they lost in their urine. Within 2 days they also reduced the amount of sodium lost in their sweat. As a result within a day or two subjects had adapted their sodium losses exactly to match their (reduced) sodium intakes. This occurred even on a sodium intake as low as 3g per day; he did not test lower salt intakes. He also showed that sweat sodium concentrations could drop to 1-10mmol/L (compared to the reported values of 50-70mmol/L in the so-called “salty sweaters” beloved of the US sports drink industry).

In time he discovered that the hormone aldosterone was responsible for this adaptation and subsequently described a condition termed Conn’s syndrome in which a tumour of the adrenal cortex secretes excessive amounts of aldosterone causing high blood pressure (and very low sweat sodium concentrations amongst many other features).

Interestingly studies of elite Kenyan runners living and training in Eldoret, Kenya show that they train up to two hours a day whilst eating a diet containing just 3 grams of salt per day. This compares to the typical average salt intake of 7-10 grams per day of sedentary individuals living in developed countries. Since the sweat of the Kenyans was still not as low as 1-10mmol/L it seems probable that they could have adapted successfully to an even lower daily salt intake.

In summary, it is clear that human athletes can adapt to much lower daily sodium intakes than they will ever wilfully choose to ingest. When the intake is higher than this minimum the excess will appear in the urine and sweat. The point is that the presence of salt in the urine and sweat in high concentrations does not mean that the athlete is at risk of becoming salt deficient as is the popular distortion of the sports drink industry. Instead the reality is that the appearance of salt in the urine and sweat in high concentrations indicates a desperate attempt by the body to adapt to an unnecessarily high salt intake. Ingesting even more salt is clearly not the correct choice.

Dear Dan,

I can't explain your observation. The value of taking gels is that they provide carbohydrate which can improve performance by correcting a low or a developing low blood glucose concentration. Puting carbohydrate in the mouth is enough to improve performance as recently reported in a British study also reported on the Time website. The brain interprets the presence of glucose in the mouth as a good sign and allows the body to exercise more vigorously as a result even before the carbohydrate is absorbed and metabolised.

My own experience in ultradistance running events was that the provision of lots of carbohydrate (25-40 grams per hour) during the second half of races longer than 42km has a much greater impact on my performance than did drinking fluids (hence my bias I suspect). We did not ingest salt in those days.

But I cannot explain how taking more carbohydrate or protein affects your fluid balance. It is not something I have thought about.

This thread is a sketch of human nature. When faced with a problem, we naturally look for a solution, hoping that more is under our control than is often the case.

There are many factors that could cause cramping that are completely beyond our control. The temperature or ph of the tissues might be sufficiently different on hot and humid days to tip the scales toward early failure. The ability of the muscle to remove by-products may be impaired. Venous blood flow may take a more superficial path from the legs to help cool the body, thereby causing several potential changes deep in the muscle.

While it certainly makes sense to control everything as best we can, delivering sufficient fluid, electrolytes, nutrients, etc. to the working muscle, it isn't always enough.

Consider from the perspective of the antelope, whose life is at stake. If given Gu, Gatorade, Endurolytes, would his end result be any different? Or would his fate be the same, being an antelope, after all?

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Coach at KonaCoach Multisport

Dear Eileen,

You are developing the syndrome of inappropriate ADH secretion (SIADH). ADH is the hormone that regulates water re-absorption by the kidneys. Once you over-secrete ADH you are unable to excrete any water that you take in excess of your requirement.

The treatment is to exactly match your daily water intake with your requirement. This can only be done by weighing yourself every few hours during these events to insure that you do not gain any weight. Because you will be travelling quite slowly in these events your sweat rate will be much lower than perhaps you suspect. Thus your fluid intake requirement will also be much lower.

There are ADH blockers that are being developed but you do not need a pharmaceutical solution. Using a scale effectively is all you need.

I'm...speechless.

It clearly fails me (as I mentioned in post #2 in the thread) because my weight loss limits are in the 4% range for onset of extreme fatigue and cramping. My body typically doesn't say "DRINK NOW" until at least 3% loss, at which point I am already deep in the hole. I'm sorry, but the experiments showing that "the very best athletes are able to sustain large fluid losses" does absolutely nothing to help those who cannot sustain large losses. To that extent, Yknot and others make a very good point...to wit...just because humans may have a wide store of slowly-or-variably-slowly-accessible Na stores does not mean it's a good idea to try to use them during a race. The same goes with calories..bonking due to hitting the readily-available glycogen store limits.

Regarding Calcium and Magnesium, I have found two consistent effects of deficiencies. Calcium deficiency is absolutely a big contributor to cramping muscles for me, partially because I'm allergic to milk and likely don't get enough. I supplement with Calcets during excersize (1 per hour roughly) and it's a big help for reducing the chances of cramping. Magnesium deficiencies always show up as "twitchy muscles," usually in the calves. This can definitely be a cramp-causer as the twitchiness expands to cramps. I found this one by searching for information on twitchy calves and RLS (restless leg syndrome).

Regarding the kind of weird animal analogy...most animals aren't INTENTIONALLY going out and racing Ironman...which is arguably well beyond the normal limits based on human evolution. You find animals like dogs, lions, giraffes, etc. sitting in the shade in the middle of the hot summer day...while us idiots are out there attempting to run beyond our limits.

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Dear Dev,

Good to hear from you again. Your hyponatremia in the Ironman was due to SIADH so clearly you are prone to conserve water under stressful condtions. Perhaps the low oxygen concentration in the airplane or simply sitting for prolonged periods are enough to activate your systems of water conservation again.

I was thinking about this on my ride today. What should one preload. Not what they can replenish on the course, the sodium and water. That stuff is easy. But the stuff that is inside the cell, like the potassium and calcium. I would make sure I was supplementing those before the race and not trying to take that stuff in during the race (since it will not get into the cell while racing).

The best and easiest recommendation for most is probably to eat a well-balanced diet and stay hydrated before the race.

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Frank,
An original Ironman and the Inventor of PowerCranks