What are muscle cramps?

A: A cramp is a sudden, involuntary tightening of a muscle or a group of muscles that a person can’t immediately relax. Because the muscle locks up all at once, it often feels like a sharp knot and can hurt for a few seconds to several minutes.

Muscle cramps occur in parts of the legs or hands as a result of dehydration, exercise or low potassium or magnesium levels. Menstrual cramps in the uterus are hormone-driven contractions to expel the uterine lining. Stomach cramps occur due to gas, infections and/or in people with irritable bowel syndrome.

In all cases, a cramp occurs when muscle cells have become stressed and start to misfire. People are at greater risk of cramped muscles if they have diabetes, thyroid problems or kidney disease or if they’re taking particular drugs.

To relieve a cramped muscle, doctors have advised pausing the stress-causing activity and gently stretching the muscle, massaging the area, applying heat to relax the tightness, and drinking lots of water. It also helps to warm up before the activity to prepare the muscles.