It hits in the last mile, or in the eleventh hour of a yard project, or at 2 a.m. in a dead-quiet bedroom — the calf locks up, the arch of the foot curls, and there is nothing to do but hobble around until it lets go. Somebody has almost certainly told you the fix is salt. Drink more electrolytes for muscle cramps and the problem goes away.
That advice isn't wrong, exactly. It's just aimed at one cause of cramping out of several, and it's sold as if it covers all of them. Here's what the research actually supports, where electrolytes genuinely help, and what to do when they don't.
The two competing explanations for cramping
Exercise-associated muscle cramps — the involuntary, painful, seizing kind that show up during or shortly after hard effort — have been argued over for decades. Two theories dominate.
The electrolyte depletion and dehydration theory
This is the one everybody knows. The idea: heavy sweating drains sodium and fluid, the concentration of electrolytes around the nerve and muscle changes, and the muscle becomes hyperexcitable and fires when it shouldn't. It's an intuitive story and it maps neatly onto a product you can sell.
The altered neuromuscular control theory
In 1997, Martin Schwellnus and colleagues at the University of Cape Town proposed a different mechanism in the Journal of Sports Sciences, and it has become the more widely accepted explanation in sports medicine. The short version: cramping is a fatigue problem in the nervous system, not a mineral problem in the blood. Read the paper.
Your muscles carry two opposing sensors. Muscle spindles sit inside the muscle belly and drive contraction when the muscle is stretched. Golgi tendon organs sit at the tendon and inhibit contraction when tension gets too high. Under accumulating fatigue — especially with the muscle working in a shortened position — spindle activity ramps up while the inhibitory signal from the Golgi tendon organs drops off. Excitation without the brake. The result is sustained abnormal spinal reflex activity, presenting as an involuntary contraction: a cramp.
The evidence that pushed the field this direction is hard to argue with. Cramps show up in cool weather and in swimmers. They appear in one muscle group while every other muscle in a systemically dehydrated body stays fine. And they respond immediately to stretching — which makes sense if you're reloading the Golgi tendon organ, and makes no sense at all if the problem is a sodium deficit in your bloodstream.
So do electrolytes help with cramps or not?
Both things are true at once, which is why the internet is such a mess on this question.
Research from Edith Cowan University found that people who rehydrated with electrolyte-enhanced water were less susceptible to induced cramping than those who rehydrated with plain water — and that the electrolyte solution left muscles more cramp-resistant than plain water did after a dehydrating session. That's a real effect worth taking seriously.
But controlled work on cramp-prone athletes exercising in heat has been considerably less flattering. In that setting, athletes given an electrolyte and carbohydrate drink still cramped at high rates while fully hydrated. What the drink appeared to change was when the cramps arrived, not whether they did.
Read those together and a reasonable conclusion emerges: electrolytes shift your threshold; they don't remove it. If you push a fatigued muscle far enough, it will cramp regardless of what's in your bottle. What sodium replacement does is stop you from arriving at that threshold early and unnecessarily.
When cramping really is a hydration problem
There's a specific pattern where the electrolyte explanation holds up well, and it's worth learning to recognize because it's the one you can actually influence with a drink.
- You're a salty sweater. White crust on a dark shirt, stinging eyes, gritty hat brim. Higher sweat sodium concentration means bigger losses over the same session.
- Long duration in heat. Multi-hour efforts, or outdoor work, where total sweat volume is genuinely large.
- You've been drinking plain water — a lot of it. This is the classic setup. Replacing heavy salty-sweat losses with unsalted water dilutes what sodium is left. Big volume, no minerals, is the version of hydration most likely to backfire.
- The cramps come late and widespread rather than in one overworked muscle early on.
If that's your pattern, sodium is a reasonable lever — and the timing matters as much as the amount. The American College of Sports Medicine's general guidance for exercise sits around 300–600 mg of sodium per hour, with heavy sweaters at the top of that band or above. Note that it's per hour, not per day: replacing steadily across a long session works better than one large dose at the start or a catch-up at the end. That's the range the two tests in this post will help you place yourself in.
When it probably isn't
Equally worth naming: the cases where more salt is not the answer, and reaching for a bigger dose just adds sodium you didn't need.
- Cramping in one specific muscle, early in a session. That's a local fatigue and conditioning signal, not a systemic mineral one.
- Cramping on cool days or in the pool, with minimal sweat loss.
- Cramping when you go harder or longer than usual. Ramping training load faster than the muscle adapts is one of the most consistent predictors of cramping there is.
- Nighttime leg cramps. These are common, often unrelated to exercise, and can have a range of underlying causes. If they're frequent or severe, that's a conversation with a clinician — not a bigger scoop of electrolyte powder.
What to actually do about it
In the moment: stretch the cramping muscle and hold it. Calf cramp — straighten the leg and pull the toes toward your shin. Hamstring — straight leg, hinge forward. It works because it restores the inhibitory signal, and it works within seconds, which no drink can claim.
Across a season: build load gradually, train in conditions resembling the ones you compete or work in, and don't jump two hours of effort onto a body conditioned for one. Fatigue resistance is the actual variable under your control.
On the hydration side: replace fluid with minerals rather than without them, and replace on a schedule rather than in one hit. Sodium, potassium, and magnesium all participate in nerve signaling and muscle contraction, and your body has no way to bank a surplus for later.
This is part of why we built burbo Lemon Berry hydration sticks around a moderate 327 mg of sodium per stick instead of a salt bomb. It puts you at the bottom of the ACSM band with one stick, which makes the long-day math simple: roughly one stick per hour of sustained sweating, each in a full bottle of water. If you're a heavy salty sweater in real heat, two in the opening hour and one per hour after still keeps you inside the guidance. A fixed 1,000 mg serving gives you no such control — you take the whole dose up front whether the day calls for it or not, and it sits heavier in your stomach while it's at it.
The ceiling worth knowing: each stick also carries a full day's folate and B vitamins, so two a day is comfortably fine and three is the practical maximum. On a genuinely all-day effort, keep the hourly rhythm but take the additional sodium from food, salt tabs, or a plain vitamin-free electrolyte alongside.
The takeaway on electrolytes for muscle cramps
Electrolytes aren't a cramp cure — the evidence just doesn't support that. Most exercise cramps are a nervous system running out of road, and the fix for that is training, pacing, and a good stretch. What electrolytes do is remove one avoidable accelerant: the dilution that comes from replacing heavy salty sweat with plain water alone. That's a real, worthwhile job, and it's the one burbo is built to do — hour by hour, at a dose you control.
Fix the fatigue. Cover the sodium, hour by hour. Stretch the muscle when it locks. That's the playbook.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. How this article was researched and written: our editorial standards.