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Leg cramps, or charley horses, are a common problem that affect the feet, calves, and thigh muscles. They involve sudden, painful involuntary contractions of a leg muscle.

They often occur while a person is sleeping or resting. They can be gone in a few seconds, but the average duration is 9 minutes. They can leave tenderness in the muscle for up to 24 hours after.

In most cases the reason for leg cramps is never found, and they are considered harmless. Sometimes, however, they may be linked to an underlying disorder, such as diabetes or peripheral artery disease.

Fast facts on leg cramps

Here are some key points about leg cramps. More detail is in the main article.

  • Leg cramps most commonly affect the calf muscle.
  • They typically only last a few minutes, but the pain can last for 24 hours.
  • They are more common in older age and during pregnancy.
  • Most often, leg cramps are no cause for concern and have no medical significance.
  • Risk factors may include dehydration, some medications, flat feet, and alcohol abuse.

Man with cramp in his leg or calf.Share on Pinterest
Cramps are generally not a sign of an underlying condition.

In most cases, there is no underlying cause and the reason why cramps happen is unclear.

They are thought to be caused by muscle fatigue and nerve dysfunction, but exactly how they happen is unclear.

It has been suggested that the way we sleep, with the foot stretched out and the calf muscles shortened, may trigger night cramps. Another theory is that cramps are more likely nowadays, as people no longer squat, a position that stretches the calf muscles.

Exercise is one factor. Stressing or using a muscle for a long time may trigger a leg cramp during or after the exertion. Cramps often affect athletes, especially at the start of a season, if the body is out of condition. Nerve damage may play a role.

Dehydration is thought to play a role. Athletes who exercise strenuously in hot weather often experience cramps. However, there is a lack of evidence to confirm this, and the theory has been disputed. Athletes who play in cool climates also get cramps, after all.

Sometimes the leg cramps are caused by an underlying condition, situation or activity.

Other conditions that may cause cramps are:

Cramps have been linked to electrolysis imbalances, but reseach has not supported these theories.

Older people are more likely to experience leg cramps. Muscle loss starts from the mid-40s and increases if the person is not active. This increases the risk of cramps.

Between 50 and 60 percent of adults and 7 percent of children are believed to experience cramps, and the likelihood increases with age.

They are more common during pregnancy.

No medication is recommended for cramps.

If a severe cramp leaves a muscle feeling tender, an over-the-counter (OTC) painkiller may help.

Quinine has been used in the past, but it is no longer recommended, according to recommendations published by the American Family Physician (AFP). The FDA issued a warning in 2010 about potentially dangerous interactions and side effects.

There is limited evidence that exercise and stretching, calcium channel blockers, carisoprodol, and vitamin B-12 may help. Multivitamins may be of some use during pregnancy.

There is no evidence that nonsteroidal anti-inflammatory drugs (NSAIDs), calcium, or potassium are of any benefit.

The following measures may also help prevent leg cramps.

  • Supporting your toes when lying down or asleep by propping up the feet with a pillow or letting the feet hang over the edge of the bed.
  • Keeping bedding loose to help prevent the feet and toes from pointing downward during sleep.
  • Wearing suitable footwear, especially if you have flat feet and other foot problems.

Keeping fit by getting enough exercise can help. If you exercise, make sure your program is suitable and that your progress is gradual. Avoid overexertion and training for prolonged periods, and always remember to warm up before you start.