People who are out of shape run an increased risk of getting cramps because poorly conditioned muscles get fatigued more easily, says Paul Davidson, M.D., associate clinical professor of medicine at the University of California in Greenbrae and medical director of the Fibromyalgia Clinic at Kentfield Rehabilitation Hospital in Kentfield, California. That's because swelling deprives the calf muscles of the nutrients they need. Also during pregnancy, the fetus draws on the mother's mineral stores, which may lead to depletion, she says. Your sleeping position may also be the culprit. When blankets press down on your foot, forcing it into a pointed position, your calf and foot muscles are shortened and a cramp can result.
Medications can trigger muscle cramps.
Diuretics, for example, which are used to treat kidney disease and high blood pressure, cause frequent urination. Because you lose minerals when you urinate, mineral balances in the body are altered. Muscle cramps can also be due to diseases, including hypothyroidism, in which the thyroid gland produces too little hormone. Peripheral vascular disease, in which the small blood vessels in the extremities deteriorate, and atherosclerosis, in which the walls of small blood vessels thicken, both cause circulatory problems and possibly cramps. Don't Cramp Your Style Lots of people get muscle cramps, and usually they are not a sign of anything serious, says Dr. Davidson.