How exactly do muscle cramps/spasms (for example, calf cramps) occur? What is the process that causes them?
In: Biology
Your muscles move by contracting, and then they expand again when at rest. When you have a cramp, the muscles have not been able to expand for whatever reason, so they remain tensed and contracted which can become painful.
One reason for this can be a lack of electrolytes. The muscles use specific ions like calcium and sodium to contract and expand, and if you don’t have enough of the right ion the muscles won’t be able to expand after contracting. This is why Gatorade has electrolytes mixed in with it. A lack of water will do the same thing.
Another reason could be the nerves sending the signal to your muscles have gotten confused, sending the signal to tense over and over again.
It could even be part of your brain mistakenly telling your nerves to send a signal to tense over and over.
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How about when you get a cramp and you can see your muscles writhing under your skin? Freaked me out the first time, also hurts like a bitch
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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