The real cause of muscle cramps and soreness

You've probably been told that dehydration or a lack of electrolytes is the main cause of muscle cramps and that lactic acid is our sworn enemy. In this article, we'll find out what the truth really is.

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.

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.