Health and Fitness Information Center

Muscle Cramps

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Cramps remain something of a mystery, and it's seldom possible to pinpoint why they occur. Still some general facts about cramps can help prevent or alleviate them.

Nighttime calf cramps usually strike in bed at night as a result of contracting the calf muscles by suddenly pointing your toes or by lying with the feet in that position. (Swimmers, who kick with their toes sharply pointed, can suffer calf spasms similar to nocturnal leg cramps.)

If you exercised strenuously earlier in the day, your muscles may tighten while you sleep and thus cramp. Similarly, if you're not used to them, wearing high heels may cause cramps.

Athletes' cramps occur during exercise for a number of reasons. The imbalance of minerals called electrolytes (potassium and sodium) in the blood, which often results from excess sweating and dehydration may cause muscles to cramp.

Another common cause is overexertion or muscle fatigue, marked by excessive tightening or the muscles and/or a build-up of lactic acid in them. Poor conditioning may also contribute to cramps.

If you seem predisposed to nocturnal calf cramps, don't point your toes while stretching, and try not to sleep with your toes pointed. Sleep on you side, and don't tuck in your blankets and sheets too tightly, since these can bend down your toes.

Your best for relief is massage and stretching. To halt the cramp, flex your foot by pointing your toes upward. Lying down and grabbing the toes and ball of your foot and pulling them toward your knee may help. At the same time, massage the muscle gently to relax it fully. Ice packs can reduce blood flow to the muscles and thus relax them. Walking may help, too, particularly if you put your full weight on your heels.