What causes muscle cramps?

What causes muscle cramps?

Muscle cramps are sudden, involuntary contractions that occur in various muscles. Commonly affected muscles include those in the back of your lower leg, the back of your thigh, and the front of your thigh. You may also experience cramps in your abdominal wall, arms, hands, and feet.

The intense pain of a cramp can awaken you at night or make it difficult to walk. A sudden, sharp pain, lasting from a few seconds to 15 minutes, is the most common symptom of a muscle cramp. However, in some cases, a bulging lump of muscle tissue beneath the skin can accompany a cramp as well.

Muscle cramps have several causes. Although most muscle cramps are harmless, some may be related to an underlying 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.

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.