eli5: why are side cramps so common when walking / running at high speeds or long distances?

Question

eli5: why are side cramps so common when walking / running at high speeds or long distances?

In: 9

Answer 1

3 reasons:

1. The muscles that control breathing (diaphragm and accessory muscles) are in the sides of your chest and abdomen and are working hard from breathing rapidly due to exertion.

2. Lactic acid builds up in the muscle tissues during exercise causing burning/cramping sensation.

3. Electrolyte imbalances caused by sweating out salts can cause cramping.