Why do muscles cramp during or after exercise?

Muscle cramps during or after exercise are most commonly caused by fatigue and altered neuromuscular control. When muscles tire, the nerve signals regulating muscle contraction become disrupted, causing the muscle to fire repeatedly and involuntarily. This is the leading explanation supported by current research. Dehydration and electrolyte imbalances, particularly losses of sodium, potassium, magnesium, and calcium, can also contribute by affecting how nerve signals are transmitted and how muscle fibers contract and relax. These minerals help regulate the electrical activity in muscle cells, so losing them through sweat can trigger involuntary contractions. Poor conditioning, inadequate stretching, and exercising in heat all increase the risk by accelerating both fatigue and fluid loss.