The patient complains of painful, visible, palpable muscle contractions, often affecting the gastrocnemius muscle or small muscles of the foot or hand. Ordinary cramps occur chiefly at rest during the night or after trivial movement but also can occur after forceful muscle contraction. Other muscle cramps are associated with exercise in the heat, occupations that cause overuse, pregnancy, hemodialysis, electrolyte disturbances, dehydration, and drug or alcohol use. Most cramps are transient in nature, but they are likely to recur after a severe episode. Following this, the muscles may be tender and painful for some time.