Hi,

The debates around cramping are where research and practice can seem to conflict.

Talk to someone who just takes a myopic look at studies, and they'll say: electrolytes don't matter, fueling probably doesn't matter, your experiences don't matter, and honestly go F yourself.

Talk to someone who listens to experiences, and you'll hear: all of that stuff matters, depending on the person, along with lots of weird things you might not be thinking of.

My guess is that what explains the offset is that there are multiple buckets of cramping situations. Let's start with a basic definition from a 2019 review study: cramping is an “intense and painful involuntary contraction of skeletal muscle.” If you've ever had a cramp, you know how much it sucks. In some cases, the muscle fully seizes and won't let go. It hurts very badly.

Given that it's involuntary, we know we're looking for something with the nervous system misfiring. Theories involve increased excitatory drive or inhibitory drive to muscles, almost like the brain and spinal cord either hold down the gas or brake. We can't really isolate cramping in studies because they seem so unpredictable (often only happening in races), and any random sample of athletes is going to be getting people from all different buckets. Put it all together, and scientifically it can seem like we are up a crappy creek with our paddle arms seizing uncontrollably.

But I get how important this question is for athletes who experience cramps, because I used to be a cramp boy. I can't emphasize enough how much it took the joy out of longer races and training days. My dad also cramps, so there is probably some genetic component (meanwhile, Megan has almost never cramped). I always read these articles being like “it's a strength issue” or similar BS and I'd think “explain why it starts in my left forearm.” When you experience these types of full-body, all-over cramps, it's so clear that it's a systems failure in the nervous system without a simple explanation.

Other cramps may be more specific to overworked muscles, usually preceding similar sparks flying in the nervous system. Either way, cramping is often coming back to central nervous system processes affecting peripheral muscular cramping. The central nervous system...What does that remind you of? If you're anything like me back in 2016 when I was so desperate to solve this problem, it brings to mind the holy grail of endurance performance: fatigue resistance. Fatigue resistance is also a central nervous system process with peripheral components.

That was the realization I had a decade ago, so frustrated with my failing muscles. Perhaps trying to solve for cramps might also point toward solutions for the fatigue resistance problem.

Now let's cut to the chase! In the decade since that moment, we have read all the research (not particularly helpful) and talked to hundreds of athletes (extremely helpful), often helping them pilot different interventions and report back (the most helpful of all). That has led to this list of ten interventions to try.

One: High Carb, but avoiding extreme pre-race loading protocols

This is the big one that can seem to change cramp trajectories over time. If an athlete practices high-carb on almost every long effort, cramping cases seem to go down precipitously. Interestingly, it only seems to happen with a major training focus, rather than being a single-day change in races. It stems back to a previous article: we don't just want to practice endurance, we want to practice stellar fatigue resistance. That likely causes some remodeling of central nervous system processes that reduce future cramping.

The remodeling might be traced to the brain itself. A 2025 study found a reduction in myelin around the brain following marathons due to metabolic stress. A 2026 follow-up study had the strange finding that the myelin reduction did not affect conduction latencies “supporting an adaptive framework linking myelin change with preserved brain function under extreme metabolic stress.” In other words, the brain adapts to these stresses, and our theory is that high-carb fueling positively changes how that adaptation occurs.

My favorite gels are Amacx, Science in Sport Beta Fuel, and Enervit.

Two: Adequate sodium and hydration intake during the event, but no abnormal sodium loading

Sodium intake is the place where you can separate whoever works in the real world and those who might not. Almost every coach/nutrition expert living in the real world talks about electrolytes and hydration as one of the primary drivers of cramps, whereas some studies say it's less important. Sodium balance is likely key at the cellular and systems level, with its role in electrical signaling for the nervous system at the forefront. Here is a full article on electrolyte intake in racing.

Anecdotally, we see more cramping with extreme loading protocols for sodium/hydration, which may change how the body sweats subsequently. The same goes for extreme carb loads, with our theory being that it could change carb/fat oxidation rates when done to excess. Keep it simple and do what you normally do, supported by small tweaks like a bit more carbs, rather than massive changes that you never practice in training. The reduction in training volume will do the rest.

I am obsessed with Precision 1000 tabs and Mortal Hydration.

Three: Magnesium supplementation

This point is related to the electrical conductivity part of the electrolyte equation, helping muscles relax after contraction. In coaching practice, I don't see this element as being as important as others, but given the stories I read elevating magnesium's importance, it's an easy-to-address option with a nightly supplement.

Some athletes I coach swear by Pillar Magnesium.

Four: Bicarb before races and long runs

This is a point we see all the time, but we're not sure exactly where it comes from. Is it the sodium load itself (some studies have found that serum sodium remains elevated for many hours)? Or is it nervous system conduction? Or something else with remodeling in training? Interestingly, the effect only seems to happen with longer-term use, so it's probably related to an adaptation process rather than the sodium load alone. Here is a bicarb tutorial.

I am a Maurten Bicarb guy, and that tutorial has our secret method that I shouldn’t talk about here. 

Five: Steep downhills in training

Eccentric loading from steep downhills likely has 2 pathways to prevent cramping. First, it reduces muscular damage and increases resilience in longer events (addressing the strength-limitation theory of cramping). These adaptations seem to affect faster twitch muscle fibers more readily, which are the likely culprit of many cramps (pure Type I slow-twitch athletes rarely complain about cramping).

Second, it could cause “neural microdamage” that leads to adaptation addressing the central nervous system. A 2020 study theorized that delayed onset muscle soreness stemmed from “acute compression axonopathy of the nerve endings in the muscle spindle.” In that model, downhill-induced soreness may address nervous system pathways that contribute to both cramping and fatigue resistance.

Six: Strength training emphasizing muscular endurance

Now we're back in uncontroversial waters. Strength training improves muscular power and endurance. Our theory is that strength should combine a small amount of heavier loading 1 or 2 times per week (like squats, which may act by similar eccentric principles as downhills) with a broader focus on muscular endurance 3-5 days per week. Single-leg step-ups seem to reduce cramping when done after most runs. Why? It's probably just a type of fatigue resistance practice, where the nervous system activates over and over and over, giving athletes a chance to adapt to loading that is difficult to achieve from running alone.

Seven: Heat training, especially hot tub and active heat

We're probably looking at multiple pathways with heat. Increasing blood volume and capillary density may help get oxygen to working muscles in a way that improves muscular contractions. Maybe it's from improved sweat dynamics, with more dilute sweat causing fewer electrolyte issues. But I think it probably relates to the simple idea that heat response is a nervous system adaptation, and training the central nervous system to alleviate core and skin temperature increases results in lower stress during long events.

Eight: Avoiding excessive tapers

Too much taper can reduce blood volume, decrease metabolic efficiency (pushing the body more toward carb oxidation at lower efforts), and perhaps even change how muscles fire. Coach Steve Magness focuses on a term “muscle tension” to describe a nervous system tuning process, and you could imagine how excessively low tension could contribute to subsequent nervous system overactivation during races.

Nine: Careful with caffeine

Caffeine or other supplements that activate the nervous system could also contribute to excessive nerve firing. Do what you normally do, and supplement on top of that based on how your body responds to stress. The same rationale points away from caffeine tapers. I like athletes to have less caffeine the day before to support sleep, but the old-school 1-week no-caffeine tapers are dangerous.

Ten: Harness the "pucker" response

How weird is it that sour, bitter, or hot tastes might reverse cramping? The theory is that the neural signal from the taste overrides the faulty signals from the nervous system. It's kind of how we sing songs from Moana at the top of our lungs when our toddler Leo is starting a tantrum, and it sometimes confuses him into being chill. These types of interventions seem to be patching up a hole in the side of the ship, rather than fixing it, so use it as a stop-gap measure. 

I usually recommend Hot Shot.

Conclusion

The nervous system is the next frontier of endurance performance. Cramps may be one of the keys that unlock how we understand the nervous system role in fatigue resistance. So thank you to cramps! You suck. But you also teach us some lessons we need to learn.

- David.