Last week a friend sent me a news article about Miami Heat star LeBron James from Game 1 of the NBA finals,. The title of the article was ” Why Heat Cramps Crushed Lebron”. Posted on the Men’s Health online site.

I must say, I was completely blown away after reading this article and many other articles like it, including video clips from several of the sports news magazine shows.

What am I talking about, you might ask? I am talking about the fact that there has never been any credible evidence suggesting that heat, dehydration, or electrolytes are the cause of what is commonly referred to as Exercise Associated Muscle Cramping (EAMC).

And yet, not only are people unaware of this little fact, but many experts in the health and science industry are as well. First, let’s take the above mentioned article on the Men’s Health website. Michael Bergeron, Ph.D., Executive Director of the Sanford Sports Science Institute is quoted as saying, “Playing in hot and humid conditions can push a player’s fluid and electrolyte loss to a dangerous level.” As dehydration sets in, subtle twitches or cramping can progressively turn into painful muscle spasms. Really?

To make matters worse, apparently Gatorade, via Twitter, attempted to capitalize on the fact that James was not sponsored by them but by another sports drink company (Poweraid), making an indirect inference that their product prevents cramping better than Poweraid. This is particularly interesting because Gatorade’s “Sports Science Institute” website boasts a non-scientific explanation for heat cramps in the “ask the expert” section. However, under Gatorade’s research section you will find only two studies addressing heat cramps. The first study not only does not prove that heat, dehydration, nor electrolytes are a cause of cramps, but also fails to find electrolyte differences between athletes prone to cramping and athletes who or not. Unfortunately the second study was a bad link.

Now, before you accuse me of having a biast opinion toward sports drinks or Gatorade products, understand that I have been a long time advocate of Gatorade and use their products quite frequently. However, I don’t use it for cramping, which I am very prone too. Rather, I use it for hydrating and something much more important for athletic performance… “sugar”.

Before I provide you with a list of compelling research as to why exercise associated muscle cramping is NOT caused by heat, dehydration or electrolyte imbalance, let me make this whole subject easy for everyone to understand.

Heat Cramps:
If heat or humidity was the cause of cramping, then why do other athletes in cooler environments also experience the same phenomena, such as swimmers, snow skiers, and distance runners performing in moderate temperatures. Not to mention the fact that cooling an area that is cramping does not relieve the symptom. Furthermore, research shows that people who cramp do not record a higher core temperature then those that do not cramp in the same event. It’s also worth mentioning when I surf in colder water less than 65°, I cramp much more earlier and frequently than when I surf in warmer water on hot humid days. I believe the reason is because in the colder water and weather, I am constantly contracting and tightening my muscles while shivering, causing my muscles to fatigue sooner. The real culprit of cramping, as you will find out in a moment.

“Heat alone is not a direct cause of muscle cramping during exercise, and therefore the term ‘‘heat cramps’’ is a misnomer, and its use should be discouraged.”

Multiple studies have failed to show a correlation between hydration levels and cramping episodes. Furthermore, if dehydration was the cause of cramping, why does cramping occur only in specific muscular areas of high use and not anywhere else in the body? Does only the hamstrings of a runner become dehydrated but not the rest of his/her body? How about a rower’s hands? A gymnast arms? A tennis player’s upper back? And do products like Gatorade really have the specificity to replenish just those areas? Of course I’m being facetious; dehydration occurs throughout the entire body and it only makes sense that other muscle groups in a person’s body prone to cramping would also cramp as well— not just the muscle groups which are currently under high use, that is if hydration was actually the cause.

Electrolyte Imbalance:
Just as with hydration, studies have failed to show a significant difference in electrolytes among those who cramp and those who do not, such as the one I referenced from Gatorade’s site. The argument as to why only specific areas of use cramp and no others would apply to electrolyte imbalance, as well. In other words, it would be systemic (over the entire body) and therefore makes no sense.

Anecdotal Evidence:
As I mentioned a moment ago, I am prone to cramping. In fact, my friend (who sent me the Lebron aricle) is fortunate enough to not be burdened by this physiological inconvenience, finds great pleasure in pointing out my physical limitation whenever I am on the ground incapacitated after riding strenuously for over 3 1/2 hours on a mountain bike. At least, that used to be the case, until he had the pleasure of experiencing this devastating physical effect just recently, after participating in a mountain bike race lasting over 5 hours. Payback LOL.

I can tell you first hand that I have spent a considerable amount of time researching and experimenting with various solutions for reducing the frequency of my cramping episodes. Over time, it has become quite evident to me that heat, dehydration, nor electrolytes are the cause of cramping. For one thing, there is clearly an association between the muscle groups I have overused and the specific sites of my cramping episodes. For example, if I happen to heavily weight train my legs and/or trail run in the days prior to a mountain biking episode, I will almost always experience EAMC in my legs… regardless of my hydration level or the ambient temperature and humidity. Furthermore, if I perform a session or two of standup paddling in the days prior to a mountain bike ride, I will almost always experience EAMC in my hands and triceps. However, if I do neither and my body is well rested, I rarely experience EAMC.

What is the cause of Exercise Associated Muscle Cramping?
So what is the cause of exercise associated muscle cramping? Truth be told, the scientific community is void of a definite answer. However, recent findings in genetic research indicate there may be a genetic link predisposing certain individuals to EAMC. A strong emphasis has also been put on a theory known as the ‘‘altered neuromuscular control’’ hypothesis. In short, repetitive high-intensity and overuse syndrome leads to excessive muscle fatigue, which causes a neuromuscular disturbance within the active muscles. However, to adequately explain what altered neuromuscular control is would be beyond the scope of this article. (But I have provided the following research at the end of this article, if you wish to indulge.) It is also worth noting that certain medications, illnesses, and injuries have also been associated with EAMC.

My own hypothesis:
Unsubstantially and without official credibility, it is my personal opinion that EAMC occurs disproportionately in individuals who possess a higher distribution rate of white muscle fiber tissue in specific muscle groups. I believe this phenomenon occurs because of a lack of mitochondria density and the inability to sufficiently reestablish an adequate ATP pool, which leads to excessive AMP fatigue and exposes an individual to altered neuromuscular control. By the way, LeBron James is apparently known for being a rather large muscular player, which is an indication of a predisposition toward white muscle fiber. LeBron James has also been quoted in the press this week stating that he is no stranger to cramping and has had to deal with it for most of his athletic career. This either strengthens my hypothesis or means Mr. James is terrible at hydrating and maintaining electrolyte balance.

So let’s put this all in perspective. LeBron James did not suffer from heat cramps during the Game 1 of the NBA finals, as most media outlets have erroneously reported. Rather Mr. James suffered from a condition known as Exercise Associated Muscle Cramping (EAMC), probably caused by overtraining and excessive fatigue… but certainly not caused by heat, dehydration, or electrolyte imbalance. Furthermore, Gatorade nor any other beverage company could’ve helped Mr. James condition. As to the claim that LeBron James unnecessarily quit the game, let me just say, as someone with personal experience with exercise associated muscle cramping, especially occurring within the leg, the level of debilitating pain can be overwhelming and I can totally understand why someone would not continue an activity at that time. Not to mention the fact that continuing could cause long-term structural damage to the muscle tissue and tendons requiring days if not weeks of recovery.


Significant and serious dehydration does not affect skeletal muscle cramp threshold frequency.
Br J Sports Med 2013;47:710-714 doi:10.1136/bjsports-2012-091501

Conclusion: Significant and serious hypo-hydration with moderate electrolyte losses does not alter cramp susceptibility when fatigue and exercise intensity are controlled. Neuromuscular control may be more important in the onset of muscle cramps than dehydration or electrolyte losses.

Collagen genes and exercise-associated muscle cramping
Clin J Sport Med. 2013 Jan;23(1):64-9. doi: 10.1097/JSM.0b013e3182686aa7

Conclusion: This study identified, for the first time, the COL5A1 gene as a potential marker for a history of EAMC.

Increased running speed and previous cramps rather than dehydration or serum sodium changes predict exercise-associated muscle cramping: a prospective cohort study in 210 Ironman triathletes

Br J Sports Med 2011;45:8 650-656 Published Online First: 9 December 2010

Conclusion: The results from this study add to the evidence that dehydration and altered serum electrolyte balance are not causes for EAMC. Rather, endurance runners competing at a fast pace, which suggests that they exercise at a high intensity, are at risk for EAMC.

Factors associated with a self-reported history of exercise-associated muscle cramps in Ironman triathletes: a case-control study.
Clin J Sport Med. 2011 May;21(3):204-10. doi: 10.1097/JSM.0b013e31820bcbfd

Conclusion: There is evidence from this study that a history of EAMC is associated with (1) exercising at a higher intensity during a race that may result in premature muscle fatigue, (2) an inherited risk (positive family history), and (3) a history of tendon and/or ligament injury.

Cause of exercise associated muscle cramps (EAMC)–altered neuromuscular control, dehydration or electrolyte depletion?”
Br J Sports Med. 2009 Jun;43(6):401-8. doi: 10.1136/bjsm.2008.050401. Epub 2008 Nov 3.

“There is not a single published study that has shown that serum electrolyte concentrations are abnormal in athletes at the time of acute EAMC, when compared with non-cramping control athletes. In contrast, there are now four prospective cohort studies, from two laboratories, in two different endurance sports that have shown no relationship between serum electrolyte abnormalities and EAMC in marathon runners or triathletes”

In summary, scientific evidence in support of the ‘‘electrolyte depletion’’ and ‘‘dehydration’’ hypotheses for the aetiology of EAMC comes mainly from anecdotal clinical observations, case series totaling 18 cases, and one small (n=10) case–control study. Results from four prospective cohort studies do not support these hypotheses. In addition, the ‘‘electrolyte depletion’’ and ‘‘dehydration’’ hypotheses do not offer plausible pathophysiological mechanisms, with supporting scientific evidence that could adequately explain the clinical presentation and management of EAMC.

Muscle cramping in the marathon : aetiology and risk factors.
Sports Med. 2007;37(4-5):364-7.

“In early anecdotal reports, cramps were associated with profuse sweating, together with changes in serum electrolyte concentrations. No mechanism explains how such imbalances in serum electrolytes result in localised muscle cramping.”

Thank you for taking the time to read my blog,

Ron Baer
ATP Lifestyle Modification

Special thanks to Valerie Gilmore for her editing expertise.