Athlete suffering from a calf muscle cramp on an athletics track

The real cause of muscle cramps and soreness

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You have cramps that wake you up at night or stop you in the middle of your workout. You've been told to drink more water, eat bananas for potassium, and avoid lactic acid. You've tried everything, but the cramps keep coming back. It's frustrating not to find a solution that really works.

Good news: Science has identified the real cause of cramps, and it's neither dehydration nor electrolytes.¹ Once you understand the real culprit, you can take effective action. What science tells us about muscle cramps:
  • Muscle fatigue is the main trigger for cramps, not dehydration.
  • Lactic acid does not cause muscle soreness; this is a persistent myth.
  • Rest and recovery are more effective than supplements.
  • Hydration remains important, but it is not the direct cause of cramps.

This article debunks myths about cramps and muscle soreness. To understand muscle pain in general, check out our article on overuse injuries.

Text by Shanna Hilaire, third-year student in the Kinesiology Bachelor's program

Muscle fatigue: the real culprit

Contrary to popular belief, muscle cramps are not directly caused by a lack of water or electrolytes. In fact, several studies show that muscle fatigue is the main trigger for cramps. When a muscle is overworked or fatigued, it can temporarily lose its ability to relax, causing a painful involuntary contraction commonly known as a cramp. This fatigue can be linked, for example, to insufficient recovery or excessive exertion.

Lactic acid: friend or foe?

Lactic acid, on the other hand, is a substance produced by muscles during intense physical exertion. Contrary to popular belief, it does not directly cause post-exercise muscle pain (soreness). However, its temporary accumulation may be responsible for the burning sensation felt during exercise.

The role of hydration

On the other hand, water is essential for the proper functioning of the body, including the muscles. It accounts for about 60% of body weight and plays a key role in regulating vital functions. Dehydration can lead to decreased performance, increased fatigue, and slower muscle recovery. However, although hydration is crucial to our well-being, it is not the main cause of cramps.

10 mini-tips to understand your pain

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10 mini-tips to understand your pain

Those who have had the greatest impact on my patients' lives. 1 per day, 2 min.

How can cramps be prevented?

Finally, to prevent muscle fatigue and, consequently, reduce the frequency of cramps, it is crucial to allow the body time to recover after exercise. In other words, rest allows muscle fibers to repair and strengthen themselves. In short, proper hydration, a balanced and healthy diet, and restful sleep are essential habits for keeping your muscles fresh and ready for your next workout.

Resources

  • McKinley, M. P., & Tarini, L. (2019). Anatomy and Physiology: An Integrated Approach (2nd ed.). Chenelière.
  • Nelson, N.L., & Churilla, J.R. (2016). A narrative review of exercise-associated muscle cramps: Factors that contribute to neuromuscular fatigue and management implications. Muscle & Nerve, 54.

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