It looked bad, LeBron getting Paul Pierced off the court, a Finals opener sliding wetly to an uneventful end, Gatorade trolling down from the ramparts of for-profit pseudo-science.


Here's the thing: We actually don't know for sure what causes a muscle cramp, despite what you may have heard from your high school football coach, or your half-marathoning buddy, or your gym-rat friend, or a sports-drink commercial. And the reason we don't know has a lot to do with Gatorade and the "science" of hydration.


Before we get to what probably happened to LeBron's body last night, we first need to look at how the myths of cramping were formed and reinforced. For this, we'll in large part lean on a six-part series on cramping (and a four-parter on hydration) by Ross Tucker of the Sports Science Institute of South Africa, as well as some of the surrounding research.

1. The Myths of Cramping

The story goes that way back, 100 years ago in the shipyards and mines, workers were cramping up, and an analysis of their sweat showed that it contained high chloride levels. That, combined with a study of some guys building the Hoover Dam who drank salty milk and recovered from cramps (no, seriously), is apparently where we got the idea that the loss of electrolytes (sodium, chloride, calcium, and magnesium) is what causes cramps. Along the way, this notion changed the prevailing wisdom that an athlete should never eat or drink during an event to the idea (that lasted until very recently) that you should drink as much as you can—even better if you can find a sports drink.

A few problems with that, though. For one, if electrolyte loss is the problem, shouldn't all the muscles be at risk for cramping? The body is sweating all over the place and you aren't just losing sodium from leg-blood, after all. But the only muscles that cramp up are the ones that are working and becoming fatigued. What's more, the concentration of electrolyte content in your sweat, even sweat with elevated electrolyte levels, is actually lower than what's typically in your body. Meaning, you aren't actually lowering your electrolyte concentration when you sweat—you're raising it.

Instead, what's happening when you're losing fluid is that you're throwing the osmolality of your body out of whack. Osmolality is the concentration of fluid in your body, and your body fights very hard to keep it in balance. You're becoming dehydrated, essentially. But even falling back to "fluids" doesn't explain things either.


In 2004 and 2005, Martin Schwellnus of the University of Cape Town ran two studies, one on an ultra marathon, the other on an Ironman. He observed a number of variables, but with regard to cramping the only hydration-related differences that showed up were that the runners who cramped had a significantly lower sodium concentration (this actually means these runners were over-hydrated) and a higher magnesium concentration—this is basically the opposite of what Gatorade promises. Crampers, in general, lost less weight (proxy for fluid loss), and the more direct measures of the fluid in their blood showed they were better hydrated, but cramped up anyway. So much for that.

(This doesn't necessarily mean that over-hydrating is the cause of the cramps, though as we'll see it can cause a host of other problems. Because certain people are more susceptible to cramps, or at least perceive themselves to be, they might just be taking the accepted remedies, to little effect. But clearly, the sports drinks aren't fixing the problem.)


2. Muscle Fatigue and Spinal Reflex

Right, so "your muscles get tired and stop working correctly" doesn't seem like it should be some mindblowing new theory. But it's only relatively recently that we've taken it seriously as an explanation for cramping. Here's how this theory is currently understood.


Muscle contraction is controlled by a nerve called the alpha motor neuron, which is in turn controlled by the regions of your brain that dictate movement and by spinal reflexes. The reflexes protect from over-stretching and over-loading, and some evidence shows that under fatigue, the "over-stretching" functions increase and the "over-loading" functions decrease. Basically, being tired means your protective reflexes don't work properly. The response of the "over-stretching" (muscle spindle) reflex is to contract the muscle to protect itself, and the "overloading" (Golgi Tendon organ) reflex is to stop muscle contraction to protect itself. When the first begins contracting too much, and the second stops regulating contraction at all, you're going to get one hell of a cramp.

As with the earlier bit about all of your muscles losing electrolytes equally, the key here is that the muscles most likely to cramp are the ones that are active. Further, they are generally ones that cross two joints (like the calf, between the ankle and knee) because the two joints together shorten the muscle, exacerbating the issue of the contraction.


The takeaway here, however, is that fatigue seems simply to cause cramps, without regard for hydration or Gatorade's secret sauce or preparation or anything other than your muscle being tired. Which leads us to LeBron, specifically, and how a very hot gym might affect him differently than others.

3. Yes, Heat Matters. But So Does Size.

When the AC went out in San Antonio, and LeBron was the only one to get all-the-way laid out, most everyone leaping on the dogpile used some version of the same, smug preamble: "Sure, the heat was bad, but it affected everyone the same." This isn't exactly true.


In general, our bodies can perform athletically only with a body temperature of up to 104 degrees. At that point, everything starts to slow down, shut down. Every species seems to have a built-in number for this—antelope can go to 107 degrees, rats to 106. This number comes from lab testing, so in an NBA Finals game, you'll probably see it spike to 105 or 106. At 107ish degrees, though, heat stroke sets in.

Once your temperature gets that high, your brain will literally stop you from using your muscles with as much force as you normally use. It's like when your computer gets too hot and everything all of a sudden slows down to a crawl—it's governing your heat to keep from liquefying your insides. This, you might reason, paves the way for the degradation in neuron activity that causes cramps.


Here's David Epstein, former Sports Illustrated senior writer and author of The Sports Gene, in an interview with Russ Roberts about why being smaller is key for performing in the heat:

Russ: Why are marathon runners small? Epstein: So, in the marathon, it's sort of twofold. One reason is because one major limiting factor in endurance is your ability to dissipate heat quickly. So at about 104° core temperature, you will slow down or stop. Unless you are taking amphetamines, which sometimes will override that and cause people to cycle or run until they have heat stroke. But you have to unload heat. And the greater the surface area of your body is compared to your volume, the quicker you unload heat. It's just like a radiator that has coils. The point of the coils is to increase the surface area to the volume to let the heat get out. And that becomes a really big advantage, because we know the limiting factor of heat dissipation. Smaller people also—because as you grow in height, your volume increases in 3 dimensions, while your surface area only in two. So you actually become sort of heavier for your size, which can be a disadvantage for running economy as well.


LeBron James, you might have noticed, is not the size of a tiny marathoner. He is quite large, and compared with people his size (he's listed at 6-foot-8) he runs more and harder and faster than anyone. And if you're bumping up against that temperature barrier in a 90-degree gym, and not dissipating heat well, and pushing past that built-in physical limit, you will suffer breakdowns, possibly like the misfiring of the alpha motor neuron, and cramps.

Given all that, it isn't surprising that LeBron specifically has suffered cramps throughout his career, including during the 2012 Finals against the Thunder. He's biggest guy with the biggest role on the sport's biggest stage, and the human body can take only so much.


4. Bullshit: Is It In You?

So why have the scientific myths about dehydration and cramping proved so durable? Partly, it's because so much of the science surrounding exercise and hydration has been underwritten by Gatorade, which obviously has an interest in pushing the notion of dehydration as a performance killer and hydration as the silver bullet. (In their book The Runner's Body, Tucker and co-author Jonathan Douglas mention one fear-mongering study that suggests that "dehydration of 2 percent causes performance to decline by up to 20 percent.")


Gatorade doesn't fund the research itself, but employs its practitioners more or less as spokespeople to talk about their findings. Why might this be unseemly? We turn to an unlikely source. Here is Darren Rovell, in his book First in Thirst: How Gatorade Turned the Science of Sweat Into a Cultural Phenomenon, as quoted by Timothy David Noakes and Dale B. Speedy in the British Journal of Sports Medicine:

In his otherwise uncritical review of the Gatorade phenomenon, Rovell touches on this legal accountability: "This lack of change (in the Gatorade formulation) has caused some people to be skeptical as to the true function of the Gatorade Sports Science Institute (GSSI) which has funded more than 120 studies in the past 17 years. Is GSSI there to develop the latest and greatest sports drink formula for the masses, or is it there to use science to best defend the status quo? Is it really possible that nothing substantial has come along in sports drink science in the past four decades that would make Gatorade a better drink? There are, after all, very few product categories that fail to evolve over four decades" (pp 194–195). "…..But it is undeniable that GSSI was also created to be part of Gatorade's powerful marketing arm" (p 195). "…..Having the Gatorade Sports Science Institute does mean walking a fine line between educating the public on hydration and perhaps using GSSI to sell product. Gatorade brand managers will tell you that educating the public is the number‐one goal, but it's impossible to ignore the fact that GSSI is a part of Gatorade, which is part of Pepsi, which is a public company that is expected to make money" (p 206).


When your methods are so barefaced as to make Darren Rovell blink, you are doing some seriously next-level overt shit. The context here is especially fantastic, as Noakes and Speedy invoke Rovell in as thorough an ethering as you'll see in scientific writing. "Lobbyists for the sports drink industry: an example of the rise of 'contrarianism' in modern scientific debate" is a response to then-director of the Gatorade Sports Science Institute Bob Murray, who had taken issue with their research.

The paper in question accused Gatorade of having, specifically and perniciously, used its Sports Science institute (and massive sponsorship dollars) to promote a way of drinking—"as much as tolerable" during exercise, which itself was a softening from even crazier baseline hourly quotas—that led to 125 cases of what they called exercise associated hyponatraemia, or a lowering of the sodium concentration in the blood. Neither sports drinks nor water can keep your sodium levels in line with where they are at a rest during prolonged exercise, and while Gatorade will have a slight improvement from water, drinking it to excess will do more harm than good. Gatorade's explicit "Drink (and buy) as much Gatorade as you can tolerate" mantra had made these people sick; some had died.


Murray disagreed, loudly, but impotently, in a letter to the scientific journal. Noakes and Speedy burned it down. Another excerpt from their response:

The point is that lobbyists like Naylor cannot act as usual scientists, according to the Feynman dictum. Rather, they must present, in the guise of an established scientific truth, a contrary position which is permanent and predetermined, and which has but one function—the advancement of the financial interests of the companies to whom they are accountable. To disguise their condition of compromise, lobbyists will usually assert that their exclusive interests are especially magnanimous, including, for example, the "welfare of athletes" and the "advancement of science", both of which they "proudly support". In fact, lobbyists should rather stick to their chosen jobs and leave benevolent actions to those who choose to be employed (at substantially more meagre salaries) specifically to serve humanity. As the covert goal of the contrarian scientist‐turned‐lobbyists is neither humanitarian nor the advancement of scientific truth, it is pointless for scientists to engage with them in scientific debate. Indeed, lobbyists retain their influence over the general public and the conduct of science, only for as long as their mission and mode of operation are not universally understood.


It's as clear-eyed a summation of the state of for-profit research arms as possible. And the fact that it took 20 years of obvious research to offset the over-drinking nonsense, and that it could well take 20 more to move a talk about cramps away from "He should have drunk more Gatorade," is just as good a summation of how well it all works.

Physiology and circumstance conspired to cut down LeBron. Gatorade wasn't exactly an accomplice, but it helped obscure the evidence.


Image by Jim Cooke, photo via Getty