[2][5] They are also often associated with pregnancy, physical exercise or overexertion, and age (common in older adults); in such cases, cramps are called idiopathic because there is no underlying pathology.
[6] Causes of cramping include[9] hyperflexion, hypoxia, exposure to large changes in temperature, dehydration, or low blood salt.
Skeletal muscles that cramp the most often are the calves, thighs, and arches of the foot, and in North America are sometimes called a "Charley horse" or a "corky".
It may take up to a week for the muscle to return to a pain-free state, depending on the person's fitness level, age, and several other factors.
Potential contributing factors include dehydration, low levels of certain minerals (magnesium, potassium, calcium, and sodium, although the evidence has been mixed),[15][16][17] and reduced blood flow through muscles attendant in prolonged sitting or lying down.
[citation needed] A lactic acid buildup around muscles can trigger cramps; however, they happen during anaerobic respiration when a person is exercising or engaging in an activity where the heartbeat rises.
Medical conditions associated with leg cramps are cardiovascular disease, hemodialysis, cirrhosis, pregnancy, and lumbar canal stenosis.
[17] Gentle stretching and massage, putting some pressure on the affected leg by walking or standing, or taking a warm bath or shower may help to end the cramp.
[17] Quinine is no longer recommended for the treatment of nocturnal leg cramps due to potential fatal hypersensitivity reactions and thrombocytopenia.
Up to 80% of athletes using statins experience significant adverse muscular effects, including cramps;[21] the rate appears to be approximately 10–25% in a typical statin-using population.
[26] Adequate conditioning, stretching, mental preparation, hydration, and electrolyte balance are likely helpful in preventing muscle cramps.