A muscle cramp is a sudden and involuntary contraction of one or more of your muscles. If you've ever been awakened in the night or stopped in your tracks by a sudden charley horse, you know that muscle cramps can cause severe pain. Though generally harmless, muscle cramps can make it temporarily impossible to use the affected muscle.
Long periods of exercise or physical labor, particularly in hot weather, can lead to muscle cramps. Some medications and certain medical conditions also may cause muscle cramps. You usually can treat muscle cramps at home with self-care measures.
Most muscle cramps develop in the leg muscles, particularly in the calf. Besides the sudden, sharp pain, you might also feel or see a hard lump of muscle tissue beneath your skin.
When to see a doctor
Muscle cramps usually disappear on their own and are rarely serious enough to require medical care. However, see your doctor if your cramps:
- Cause severe discomfort
- Are associated with leg swelling, redness or skin changes
- Are associated with muscle weakness
- Happen frequently
- Don't improve with self-care
- Aren't associated with an obvious cause, such as strenuous exercise
Overuse of a muscle, dehydration, muscle strain or simply holding a position for a prolonged period can cause a muscle cramp. In many cases, however, the cause isn't known.
Although most muscle cramps are harmless, some may be related to an underlying medical condition, such as:
- Inadequate blood supply. Narrowing of the arteries that deliver blood to your legs (arteriosclerosis of the extremities) can produce cramp-like pain in your legs and feet while you're exercising. These cramps usually go away soon after you stop exercising.
- Nerve compression. Compression of nerves in your spine (lumbar stenosis) also can produce cramp-like pain in your legs. The pain usually worsens the longer you walk. Walking in a slightly flexed position — such as you would use when pushing a shopping cart ahead of you — may improve or delay the onset of your symptoms.
- Mineral depletion. Too little potassium, calcium or magnesium in your diet can contribute to leg cramps. Diuretics — medications often prescribed for high blood pressure — also can deplete these minerals.
Factors that might increase your risk of muscle cramps include:
- Age. Older people lose muscle mass, so the remaining muscle can get overstressed more easily.
- Dehydration. Athletes who become fatigued and dehydrated while participating in warm-weather sports frequently develop muscle cramps.
- Pregnancy. Muscle cramps also are common during pregnancy.
- Medical conditions. You might be at higher risk of muscle cramps if you have diabetes, or nerve, liver or thyroid disorders.
These steps may help prevent cramps:
- Avoid dehydration. Drink plenty of liquids every day. The amount depends on what you eat, your sex, your level of activity, the weather, your health, your age and medications you take. Fluids help your muscles contract and relax and keep muscle cells hydrated and less irritable. During activity, replenish fluids at regular intervals, and continue drinking water or other fluids after you're finished.
- Stretch your muscles. Stretch before and after you use any muscle for an extended period. If you tend to have leg cramps at night, stretch before bedtime. Light exercise, such as riding a stationary bicycle for a few minutes before bedtime, also may help prevent cramps while you're sleeping.