Leg cramps, or Charley horses, are a common problem that affects the feet, calves, and thigh muscles. They involve sudden, painful, and 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, there is no identifiable reason why they happen, and they are harmless. Sometimes, however, they can indicate an underlying disorder, such as diabetes or peripheral artery disease.

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In most cases, people do not know why leg cramps happen, although there are a number of theories.

Some research suggests that muscle fatigue and nerve dysfunction may play a role.

Sleeping with the foot stretched out and the calf muscles shortened may trigger night cramps.

Another theory is that cramps are more likely nowadays, as most people no longer squat, a position that stretches the calf muscles.

Exercise is a 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 their body is out of condition. Nerve damage may play a role.

Some experts believe dehydration and electrolyte imbalances may contribute. Athletes who exercise strenuously in hot weather often experience cramps. However, scientific evidence has not confirmed this connection. Athletes who play in cool climates also get cramps, after all.

Sometimes leg cramps are caused by an underlying condition relating to the nervous system, circulation, metabolism, or hormones. Some medications can also increase the risk.

Conditions that may cause cramps include:

Medications that can trigger cramping include:

  • iron sucrose (Venofer)
  • conjugated estrogens
  • raloxifene (Evista)
  • naproxen (Aleve)
  • teriparatide (Forteo)

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

Research suggests that 50–60% of adults and 7% of children experience cramps, and the likelihood increases with age.

The American Academy of Orthopaedic Surgeons (AAOS) suggest the following to ease cramping:

  • Stop the activity that caused the cramp.
  • Stretch and massage the muscle.
  • Hold the leg in the stretched position until the cramp stops.
  • Apply heat to muscles that are tight or tense.
  • Use cold packs on tender muscles.

Some people use supplements, such as magnesium, to reduce muscle cramps. However, a 2020 review that looked at older adults concluded that they were unlikely to benefit from this treatment. For other contexts, such as pregnancy, there is not enough evidence to show whether supplements help.

Stretching before bedtime may help, but evidence is limited.

No medication is likely to prevent leg cramps.

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

In the past, people used quinine. However, the Food and Drug Administration (FDA) urge people not to use this, as it may have 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.

Here, learn more about treating leg muscle cramps.

If there is no underlying cause, leg cramps will probably get better without treatment.

Walking on tiptoes may help stretch the muscles and relieve a cramp.

Stretching exercises may help. If the cramp is in the calf muscle try the following stretches:

Hamstring muscle stretch

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  1. Sit on the floor with legs straight out in front.
  2. Pull the toes up toward the knee, to stretch the calf muscle.
  3. Hold for 30 seconds.

Calf muscle stretch

  1. Stand about one meter from a wall with both feet flat on the ground.
  2. Lean forward against the wall with the arms outstretched and the hands flat on the wall. Keep the heels on the ground.
  3. Hold for 10 seconds, then gently return to an upright position.
  4. Repeat 5-10 times.

Quadriceps muscle stretch

  1. Stand up straight, holding a wall or chair for support if necessary.
  2. Pull one foot up toward the buttocks, grasp and ankle, and hold the foot as close to the body as far as possible.
  3. Hold for 30 seconds, then repeat with the other foot.

Doing these exercises may help relieve or prevent cramps. They can also serve as a warm up before exercise.

The following measures may also help prevent leg cramps.

  • Support the toes when lying down or asleep by propping up the feet with a pillow.
  • Keep bedding loose to help prevent the feet and toes from pointing downward during sleep.
  • Wear suitable footwear during the day, especially if a person has flat feet or other foot problems.

Keeping fit by getting enough exercise can help. If a person does exercise, they should make sure their program is suitable and that their progress is gradual. Avoid overexertion and training for prolonged periods, and always remember to warm up before starting.

Leg cramps are not usually a cause for concern, but sometimes they can indicate an underlying problem. If cramps are severe or happen frequently, it may be a good idea to seek medical advice.

The doctor may carry out tests to try to identify an underlying cause. If the person is taking medications that can trigger cramps, the doctor may adjust the dose or change the drug.

Leg cramps are a common problem that usually happen for no identifiable reason. Stretching and massaging the muscle can often bring relief.

In some cases, however, there may be an underlying cause that needs medical attention. If cramps are severe or frequent, consider consulting a doctor.