What are muscle cramps?

Muscle cramps occur when all of the fibers in a muscle contract at once. They usually last for a few moments and vary in intensity from mild flutterings of the muscle to severe spasms. Cramps are generally caused by low levels of minerals in the body, dehydration, an injury, or obstruction of blood flow to the working muscle. Muscle cramps, most commonly in the legs, may result from peripheral vascular disease in which the vessels supplying blood to the working muscles are narrowed by atherosclerosis (angina pectoris, that biting or crushing chest pain that plagues millions of Americans, is essentially a cramp in the heart muscle resulting from the same cause, narrowing of the coronary arteries).

A muscle cramp is a strong, painful muscle contraction or tightening that comes on suddenly and lasts from a few seconds to several minutes. Soreness in the muscle may last for hours after the hard, tense cramp has stopped.

The cause of muscle cramps is not always known. Muscle cramps may be brought on by many conditions or activities, such as:

• Exercising, injury, or overuse of muscles
• Dehydration
• Pregnancy
• Exposure to cold temperatures, especially to cold water
• Other medical conditions, such as blood flow problems (peripheral arterial disease), kidney disease, thyroid disease, and multiple sclerosis

Also, many medicines can cause muscle cramps.