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Why Do Muscles Cramp During Exercise?

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Exercise crampsmuscle cramps during exercisedehydration mythrunning crampsexercise fatiguehydration

Exercise cramps can have several causes. Learn why fatigue may matter, what to do when a cramp starts, and when to seek advice.

Cover image for Why Do Muscles Cramp During Exercise?.
Why Do Muscles Cramp During Exercise? — AudioAlona Short English narration about causes of exercise cramps and practical steps.
A painful calf cramp starts late in a long run. The first thought is often, “I must be dehydrated.” Sometimes losing fluid and salts matters, especially in heat. But a cramp does not always mean you need more water or electrolytes—minerals such as sodium that help the body work.
Welcome to the Health and Wellness community on Spark, a voice-first blogging platform where we share experiences, learn from each other, and connect in communities.
Today we’ll learn why exercise cramps may have more than one cause, what a cramp can tell you about your training, and three safe steps to take when it happens.

Why cramps are not always about dehydration

Researchers have studied athletes who cramp and found that dehydration or low blood minerals do not explain every case. A 2026 review of nine studies with more than 11,000 athletes found that a past cramp was the clearest predictor. In the studies, people who had cramped before had 4.4 times the odds of cramping again.
That does not predict any one person’s risk. The review did not find consistent links with many commonly discussed factors, including hydration measures and general training patterns. That does not prove those factors never matter; it shows that the evidence is mixed and often limited.
Muscle fatigue and changes in how the nervous system controls a hard-working muscle are also possible contributors, as described in a review of exercise-cramp theories. There is no proven one-size-fits-all prevention trick.
That matters because taking extra salt or drinking large amounts of water is not automatically the answer. Both can be harmful in the wrong situation. A cramp is also not proof that you did something wrong.

Three steps to try when a cramp starts

  1. Ease off and gently lengthen the muscle. Stop or slow down, then try a comfortable stretch. Do not force a painful movement. Rest in a safe place, especially if you feel dizzy or unwell.
  2. Cool down and drink sensibly. If it is hot, move to shade or a cooler space. Sip according to thirst and conditions rather than forcing a large volume quickly. Electrolyte drinks may be useful in some long, hot, sweaty efforts, but they are not a universal cramp cure.
  3. Look for a pattern later. Did the cramp follow a sudden increase in pace, hills, duration, or heat? Have similar cramps happened before? That information can help you make gradual training changes or talk with a clinician.

The takeaway

The lesson is that exercise cramps can have several causes. Manage the moment gently, avoid extreme fluid or salt fixes, and look at training and conditions if cramps keep returning.
Remember: ease off, cool and hydrate sensibly, look for a pattern. What is one training detail you could track next time?

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Sources and further reading

  • Miller and colleagues, “An Evidence-Based Review of the Pathophysiology, Treatment, and Prevention of Exercise-Associated Muscle Cramps,” Journal of Athletic Training (2022): review.
  • Costa and colleagues, “Risk Factors for Exercise-Associated Muscle Cramps: A Systematic Review With Meta-Analysis” (2026): review of nine studies and 11,274 participants. Previous cramp history was the clearest predictor; the review assessed risk factors, not prevention programs.
  • Schwellnus, “Cause of Exercise Associated Muscle Cramps (EAMC)—altered neuromuscular control, dehydration or electrolyte depletion?”: review.

About the author

Alona, I founder and CEO behind Spark (My Founders) and Zai. Welcome. Please reach out if you have any questions or suggestions. We thank you for being here!

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