These cramps can be painful but usually are harmless, and for most people they do not happen very often. Not exercising enough, or abruptly increasing the amount of exercise, may help cause nighttime leg cramps. They typically start after walking for a moderate distance at an ordinary pace or after a short distance when walking quickly. Standing still for a few moments causes these cramps to diminish, but they begin again after a similar amount of walking. Parts affected Any of the muscles in your thigh, calf, or foot may become cramped during the night.
Claudication normally affects the calf muscles only.
Related symptoms Cramps usually are accompanied by a sharp or aching pain and a slight bulging of the affected muscle. Trying to move the cramped muscle only makes it contract more tightly. Associations Leg cramps at night can result from strenuous exercise earlier in the day, or there may be no apparent single cause. Some disorders can bring on nighttime leg cramps, however, including Parkinson's disease, diabetes mellitus, spinal cord lesions, and hypocalcemia, a disease associated with calcium deficiency. Patients receiving dialysis for kidney disorders and some types of chemotherapy for cancers also may suffer leg and foot cramping at night.