How exactly do muscle cramps/spasms (for example, calf cramps) occur? What is the process that causes them?
In: Biology
Inside each cell, oxygen is needed to respire, which is the process that converts food into energy. This is known as “aerobic respiration”. They can respire without oxygen — known as “anaerobic respiration” — but this is way less efficient plus it results in the production of lactic acid. When our lactic acid levels get too high, muscles go into spasm in an attempt to make us stop using the muscle.
This is the biological mechanism at work which produces cramps. Typically it comes from over-exertion but there are other causes, such as dehydration or a lack of electrolytes, which both interfere with normal processes and can result in a lactic acid build up. I used to get bad leg cramps 8-12 hours after an intense rugby or hockey match (I’m a sprinter, not a long distance runner, I can only guess I ran too long!) and once in my arms (!) after getting severely dehydrated without treatment in a remote part of the world.
When you hear of special forces soldiers or long distance runners suddenly dying from exhaustion, usually it’s due to them pushing through these spasms and getting too high a lactic acid level.
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