Let’s Solve Your Muscle Cramps
Athletes have always suspected hydration, but the truth is more complex
Late on the run at Challenge Penticton in 2014, barely holding on to second place but only a few minutes, I started to feel my hamstring begin to tighten and quiver—the nascent signs of a coming catastrophic cramp. Holding off Simon Cochrane in 3rd required a kind of hobble-hop-run to the finish line, running ugly but hanging on my spot. My hamstring felt like a slack-line under tension: wobbly and precarious. I hobbled to a chair in the finish chute and sat down relieved—I’d managed to finish before the cramps had taken me out of the race.
Over 60% of triathletes and between 20-70% of cyclists cite cramps as a significant obstacle to achieving their goals. You and me and are not unsual—we are normal in our struggle with cramps. In the last 40 years, however, we’ve been sold an incomplete truth: that simply focusing on hydration and electrolyte balance will save us, but research in the past 15 years says different.
Today we’re gonna talk about what a cramp is, what the various causes of cramps are (spoiler: NOT just electrolytes and hydration), and what, finally, you can actually do about them.
What IS a cramp in the first place?
A cramp is a “sudden, painful, involuntary contraction of one or more skeletal muscles.” The kind of cramp we’re talking about is called an “Exercise Associated Muscle Cramps,” or EAMCs. EAMCs tent to strike actively working muscles that cross two joints, like your hamstrings, quads, and calves…the three muscle groups most likely to cramp. EAMCs also tend to show in the latter half of events, which is our first clue in our project of splitting the causes of cramps from just hydration and electrolyte issues. Cramps tend to show up in the final quarter of the race, as anyone who has raced at the edges of their abilities knows palpably. If cramps were only due to electrolyte and hydration problems, we’d see cramps intensify steadily over the second half of the race as you dehydrate at a constant rate. Instead athletes are generally OK until the final quarter of the event and THEN begin suffering cramps. Our solution will entail something other than electrolyte losses and dehydration.
Our second clue comes from one of the fixes for cramps: light stretching of the affected muscle. You can’t stretch fluid and salt back into your muscles, and light stretching directly affects the motor units of the muscles in question—it sounds like there is a link between cramps and muscular function (or dysfunction).
Let’s go and see what the actual story is.
The different causes of cramps
Let’s set up our straw man, first: the hypothesis that hydration and electrolyte losses power cramps alone. We see evidence for this in miners and steelworkers, cited in a 2019 study. Cramping in those workers resolved with salt replacement, and other studies of tennis players and American football players saw that low sodium concentrations correlated with cramping.
That sounds conclusive, but—as with many exercise studies—not so fast, Broheim.
In controlled studies, researchers saw that crampers and non-crampers in the same race have indistinguishable sweat sodium and hydration profiles, and cramps can be induced in well-hydrated athletes. This doesn’t mean that the dehydration hypothesis is wrong, just incomplete. Let’s flesh it out.
A 2022 review of articles published between 1900 (yes) and 2020 results in an unambiguous conclusion: EAMCs are not adequately explained by dehydration or electrolyte deficits alone. Across four studies, athletes who cramped and those who did not had similar sweat sodium concentrations, plasma electrolytes, and hydration status when diet, environment, intensity, and duration were controlled. EAMCs can be induced experimentally in well-hydrated athletes with normal electrolytes, and they can occur after voluntary contractions of an isolated muscle. The authors conclude that the principal driver is altered neuromuscular control, especially when a fatigued muscle is contracted in a shortened position (emphasis mine).
The crucial work in that last sentence is “fatigued.” Cramps happen primarily in a fatigued muscle, which is the likely cause for cramps clustering late in a race. How does fatigue appear? Well, primarily by training and racing harder than your training has prepared you for. Say you’ve prepared to ride a 70.3 bike leg at 200 watts, but once you start you get excited, feel good (everyone feels good at the beginning, Broheim) and ride the course at 220w, a full 10% above what you’ve training for.
Somewhere along the way you will run out of watts! This is not at all how it works, but it’s a good illustration. If your capacity is to ride 2.5 hours at 200w, you will exceed your capacity before 2.5 hours if you ride at 220w. So pacing yourself is crucial for fending off cramps, as is actually completing the training necessary to achieve your goal.
Heat makes all of this worse, because heat will speed up dehydration and electrolyte losses AND lower your capacity to do work. This is a moment when I’m going to urge you to get your heart rate straps back out, because heart rate is an EXCELLENT indicator of internal stress. You’ve trained to ride 200w for 2.5 hours, and you usually see a HR of 140 BPM at that intensity in normal conditions. In the heat, however, you see a heart rate of 150 when at 200w. Even though the watts are the same, they are “costing” you more, so you will fatigue faster. Couple that fatigue with the dehydration and you have a perfect environment for cramps to derail your event.
There is also a clear nervous system component that is part of the fatigue hypothesis: the cramp originates in the spinal column, NOT in the muscle itself. Messages between the muscle and the spinal column get scrambled when the muscle is fatigued, and suddenly the communication between the two degrades. That lack of communication is a cramp: the nervous system is sending a signal the muscle can’t understand or process, and the result is a cramp. We’ll get into why this is important in just a minute, but the takeaway should be obvious by this point: anything that contributes to fatigue can cause a cramp. Things that contribute to fatigue include (but are not limited to):
Heat
Dehydration
Glycogen depletion
Sleep issues
Pacing
Insufficient conditioning/fitness for a given effort (which is just another way to say “pacing”)
Stress of all types (family, work, friends, training)
How to limit the appearance and severity of cramps
You won’t like this, Broheim, but in order to stave off cramps you’re both going to have to A) train more consistently and B) build up some race-specific capacity in your training. The biggest predictor of cramping is a mismatch between ability and intensity or endurance. As we’ve already said: if you ride too hard you burn through your fitness budget sooner than you’ve trained for, and cramps will become likely. The answer here? Train more, or, if you haven’t been training enough to achieve your goal, then adjust your goal. Either lift the amount of money in the budget OR downgrade the purchase you want to make, in other words. Wishing or believing you can do something won’t make it so, manifesters. You gotta put in the work.
Pace yourself. Aim to ride more conservatively in the first half and then pick it up in the second half. No, this is not “go hard” and then “go harder.” You can try that and let us know how it goes. This is “ride or run at an intensity that allows you to lift your effort in the second half of the race. Effective pacing insulates you from cramps, because you don’t burn through your fitness budget too soon.
There is strong support, too, for using products and compounds that activate the TRPV1 (Transient Receptor Potential Vanilloid 1) and TRPA1 (Transient Receptor Potential Ankyrin 1) receptors. Sorry, Broheim—that was a mouthful. You don’t really need to know what those are/mean, but we do know from that 2019 study already mentioned that using something like vinegar, pickle juice, capsaicin (chili), allyl isothiocyanate (mustard, wasabi), cinnamaldehyde (cinnamon), and gingerol (ginger) can change the conditions in the spinal column that we associate with cramping. A small volume of pickle juice (under 100ml) can relieve cramps 45% faster than using no fluid, and the effect happens too fast to be linked to electrolyte replenishment. This odd trait of spicy compounds is the reason you saw products such as Hot Shot marketed in the last decade, which taste awful but actually work quite well.
Finally, know thyself. You should know the following:
How much fluid you lose each hour when you exercise. This is a very simple test that you can do on your own. Download this spreadsheet and follow the directions here.
How much sodium you lose per liter of sweat. This one you can’t really do on your own, but I can do it for you if you come to one of our camps or if you hire me to come and give you a sodium content test. This number is primarily genetically determined, so you don’t have to worry about testing multiple times. Once you know your number, it’s yours for life.
Aim to replenish between 70-80% of your fluid and sodium losses per hour. Broseph, for example, loses 1.2l of sweat per hour and his sweat has 1000mg of sodium in it per liter. A solid hydration program would replenish 900ml of fluid per hour along with 750mg of sodium.
Make sure you’re also consuming carbohydrates, since glycogen depletion is a driver of fatigue.
CONCLUSION
Cramping, I hope you’ve seen, is not completely about what you drink, and hydration/electrolytes might be one of the smaller contributors to cramping (which doesn’t mean you should ignore it!). Cramps are what we call multifactorial, which simply means there are often several different factors in play when you cramp.
Be honest with yourself about the why: very likely you went too hard or didn’t prepare effectively in your conditioning. Instead of being offended, use the information as redirection: how can you change your approach to be better in the future? You can train more and train smarter, making sure you get some race-day specific training on the calendar. Make sure you lift weights so that your muscles are strong, because weak muscles fatigue faster. Carry something like pickle juice or another product specific to interrupting the cramp: capiscum mouth sprays (probably not straight pepper spray in the mouth, Broheim) such as HotShot or the like. Finally, make sure your hydration and nutrition plans are dialed in and practiced, because dehydration and electrolyte loss are drivers of fatigue too, and if you’ve learned anything from this article it’s that fatigue, not dehydration, is the main cause of cramps.