Dehydration & Muscle Cramps

What Causes Them & How To Avoid Them

by | Jun 15, 2021 | 1 comment


The most common complaint fielded at First Endurance about endurance training is cramping, known officially in scientific literature as Exercise-Associated Muscle Cramping (EAMC).

This complaint is even more common than bonking, because the latter has an obvious cause and solution. EAMC, it turns out, doesn’t.

In this blog installment, Dr. Bucci explains how First Endurance products use the latest scientific research and a refusal to accept axioms in product formulation in order to actually prevent cramps , not just treat them once they occur.

Challenging Assumptions

EAMC is sudden, painful muscle cramps during or right after exercise, and it can range from minor and annoying to extremely painful and debilitating. We’ve been taught to stretch, hydrate, and consume salt to prevent it, but observational and experiential evidence tells us that these practices can decrease cramping—but not as much as expected or hoped.

Despite common assumptions about preventing it, EAMC still happens regularly: 30-67% for American football, cycling, marathons, rugby, triathlons and just about every other long-term work and exercise (Troyer 2020). Because of this commonality among endurance exercises, the field of preventing cramps has suffered from complacency as to pursuing the cause and is instead focused on treating the cramps once they occur.

For those who just want the answer, it’s magnesium

By parsing scientific research and reviewing clinical studies related to both to EAMC and to various types of cramps and muscle spasms unrelated to exercise, I’ve identified a correlation between a specific electrolyte and actual prevention, not just treatment, of cramping and muscle spasms.

For those who just want the answer, it’s magnesium; for those who want to know more about the discovery process that led me to magnesium, I’ll begin with a background on the two predominant schools of thought—or “cramp camps”—related to the study of EAMC.

Fluid/Electrolyte Imbalance Theory

The predominantly assumed cause of EAMC is Fluid/Electrolyte Imbalance Theory (FEIT), which is what informs the hydration mixes we all consume while exercising. Viewed through the lens of FEIT, running out of water and sodium are the chief culprits of cramping because they are obvious.

This is accepted beyond athletics. Worker safety organizations, for example, advocate avoiding dehydration and taking salt for workers who sweat profusely in hot conditions—think coal miners and construction workers in the summer; however, they still get cramps in winter’s cold without sweating their way to imbalance. Likewise, many endurance athletes maintain proper hydration and salt intakes during exercise, but still have EAMC, usually right when they need to push at the finish and again despite preventing the fluid/electrolyte imbalance at the heart of FEIT.

Supplemental methods like eating bananas have also not provided complete solutions, and low levels of potassium and sodium at race endings don’t routinely correspond with instances of EAMC. Even salinized IV fluids administered before events to ensure proper levels haven’t been shown to prevent EAMCs any better than oral hydration or sports drinks.

So although FEIT helps many individuals and should definitely still be applied to endurance exercise, EAMCs are still prevalent. Don’t stop hydrating like you do now, but know that our current common practices to prevent cramping are far from perfect, as evidenced by the observational disparities detailed above and the second of the two dominant cramping theories, which I’ll discuss next.

Altered Neuromuscular Control Theory

These observational disparities started a new line of research called Altered Neuromuscular Control Theory (ANCT). The demon in ANCT is muscle fatigue sending signals to spinal cord neurons via normal nerve connections that in turn send mixed signals to contract, which leads to cramping by telling your muscle to contract and relax at the same time. Eventually, the fatigued muscle only sees contract commands, resulting in EAMC.

This isn’t the clear-cut cause of exercise-related cramping, though, as most of the scientific evidence informing ANCT is from carefully controlled lab settings in which electrical signals are applied to muscles to induce EAMC. Because cramping is unpredictable and because real-world athletes are bodies in motion, conducting research on ANCT in real-life settings is difficult and prevents thorough scientific rigor; however, ANCT has verified that stretching and massage is a valid way to treat muscle cramps, just not to prevent them. So far, ANCT research has not found a way to control neuromuscular connections to prevent cramps.

Who’s Right? Everyone!

There is a commonality between FEIT and ANCT theories for causing cramps: both are useful as components of a larger, comprehensive understanding of cramping during exercise. The culprit identified by both theories is nerve cells misfiring, which does explain why most EAMCs are in the most-used muscles (calf, lower leg, feet, hands, and forearms).

FEIT proponents argue that electrolyte shifts from interstitial to intravascular spaces make the nerve-muscle connection hyperexcitable, sparking misfires as unwanted contractions. It’s super difficult to study this process on a microscopic scale during real-life exercise, and it’s clear that just measuring whole-body sodium levels or sweat losses is not good enough to see that localized micro-difference.

The ANCT crowd looks at where those hyperexcitable signals go (spinal cord neurons) and see the problem there. The problem is there, but it’s also more local to the muscles, where the FEIT crowd sites it. The body is a system, and every link in the chain plays a role.

Looking Beyond Exercise

To better understand the situation, it’s useful to consider non-exercise cramp causes in other areas of the body for deeper insights to EAMC.

Cramps (also called spasms) in blood vessel muscles can cause fatal constrictions in arteries. Contractions or spasms in uterine muscles prematurely before labor is another well-studied nerve-muscle cramping event. Interestingly, intravenous magnesium therapies have been used to treat both conditions with some—but not complete—success. Most of these persons exhibited low magnesium levels or poor magnesium intakes, so the level of success shows that a missing link between nerve-muscle connections leading to cramps may often be magnesium.

High-Level Field Testing

I’ve had success applying this theory in practice. During my Certified Clinical Nutritionist days, I saw ranked tennis players and race car drivers suffer from debilitating cramps even though they were getting enough water, salt, and food. After seeing case studies of magnesium preventing cramps in scientific literature, I recommended magnesium supplements, and after a few days to weeks the athletes did not have EAMC.

At the time I thought it must have been their individualities that were corrected to restore adequate magnesium status; it turns out it’s not so individual—more like a common, widespread magnesium intake deficiency that impedes normal nerve and muscle functions and increases cramping, even when other electrolytes like sodium and potassium are at healthy levels.

Magnesium & First Endurance

First Endurance has been using significant amounts of magnesium (along with sodium, chloride, potassium, and calcium) in EFS, EFS-PRO, and Liquid Shots from the beginning, and has received much feedback about reduced EAMC in endurance athletes.

Like anything else in the body, giving too much of anything—even something inherently beneficial like magnesium—can imbalance internal systems, resulting in abnormal functions that manifest as a null effect or even toxicity. That takes a LOT of magnesium, though—far more than products like hydration mixes provide, and the inclusion of all five electrolytes means First Endurance formulas further reduce the chance of any potential imbalance.

Once you’ve got a grasp of magnesium nutriture, physiology, and biochemistry, it’s easy to see how magnesium helps both muscles and nerves to prevent EAMCs, essentially checking the boxes of both theories of EAMC. But how to administer magnesium right isn’t easy or simple—fortunately, we’ve solved those issues with EFS, EFS-PRO, and Liquid Shots, and I’ll map the difficulties in the next blog installment.

Luke Bucci PhD

Luke Bucci PhD

Chief Scientific Officer

Dr. Bucci is the industry leader in sports nutrition. He’s also an accomplished author and lecturer and holds multiple patents and patent applications on clinical laboratory testing methods and nutritional supplements.
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