Leg cramps

Leg cramps are a common and usually harmless condition. They cause the muscles in your leg to suddenly become tight and painful.

Symptoms of leg cramps

A leg cramp is an episode of sudden pain in the muscles of the leg. It’s caused by an involuntary contracting (shortening) of the leg muscle.

Cramps usually occur in the calf muscles, although they can affect any part of your leg. This includes your feet and thighs. Cramps can last from a few seconds up to 10 minutes. Thigh muscle cramps tend to last the longest.

During a cramping episode, the affected muscles will become tight and painful and the feet and toes will be stiff.

After the cramping has passed, you may have pain and tenderness in your leg for several hours.

Cramps often happen during the night when you’re sleeping.

When to get help

Leg cramps might be a sign of a more serious health condition.

Speak to your GP urgently if:

  • leg cramps last longer than 10 minutes and don’t get better when you start to move
  • leg cramps develop after you’ve come into contact with a substance like mercury, lead or dirt that gets in a cut

If your GP is closed, phone 111.

Speak to your GP if:

  • your leg cramps are affecting your quality of life
  • you’re having frequent leg cramps
  • your leg cramps are interfering with your sleep
  • you also have numbness or swelling in your legs
  • your leg muscles are shrinking or becoming weaker

Your GP will ask about your symptoms and examine your legs and feet. They may also ask if you have other symptoms, like numbness or swelling. This may be a sign that you have secondary leg cramps caused by an underlying condition.

In this case, you may need further tests, like blood tests and urine tests, to rule out other conditions.

Causes of leg cramps

The cause of leg cramps is sometimes unknown (idiopathic). In other cases, there may be an underlying condition or identifiable cause (secondary leg cramps).

Idiopathic leg cramps

Idiopathic leg cramps may be caused by:

  • abnormal nerve activity during sleep
  • excessive strain placed on leg muscles, for example during exercise
  • a sudden restriction in the blood supply to the affected muscles

Also, tendons naturally shorten over time as a person gets older. This may explain why older people are particularly affected by leg cramps. Tendons are tough bands of tissue that connect muscles to bone. If your tendons become too short, they may cause the muscles connected to them to cramp.

Secondary leg cramps

Secondary leg cramps are caused by an underlying condition or another identifiable cause like:

  • pregnancy – the extra weight of pregnancy can place strain on the leg muscles, making them more vulnerable to cramping
  • exercise – leg cramps are often experienced when resting after exercise
  • neurological conditions – for example, motor neurone disease or peripheral neuropathy
  • liver disease – if your liver stops working properly, toxins will build up in your blood, which can make your muscles spasm
  • infection – some types of bacterial infection, like tetanus, can cause muscle cramps and spasm
  • toxins – in some people, high levels of toxic (poisonous) substances in the blood, like lead or mercury, can cause leg cramps
  • dehydration – in some people, low levels of water in the body can lead to a drop in your salt levels, which can trigger muscle cramps

Treating leg cramps

Medication is usually only needed in persistent cases where cramping does not respond to exercise.

If you have secondary leg cramps, treating the underlying cause may help relieve your symptoms.

Leg cramps that occur during pregnancy should pass after the baby is born.

Treating cramps that occur as a result of serious liver disease can be more difficult. Your treatment plan may include using medications like muscle relaxants.


Certain medications have been known to cause leg cramps in a small number of people. If you develop leg cramps after starting a new medication, speak to your pharmacist.

Never stop taking a prescribed medication unless your GP or healthcare professional advises you to do so.

Stretches for leg cramps

Most cases of leg cramps can be relieved by exercising the affected muscles. Exercising your legs during the day will often help reduce how often you get cramping episodes.

To stretch your calf muscles:

  1. Stand with the front half of your feet on a step, with your heels hanging off the edge.
  2. Slowly lower your heels so that they are below the level of the step.
  3. Hold for a few seconds before lifting your heels back up to the starting position.
  4. Repeat a number of times.

Preventing leg cramps

If you often get leg cramps, regularly stretching the muscles in your lower legs may help prevent the cramps or reduce their frequency.

You might find it useful to stretch your calves before you go to bed each night.

If you lie on your back, make sure that your toes point upwards. Placing a pillow on its side at the end of your bed, with the soles of your feet propped up against it may help keep your feet in the right position.

If you lie on your front, hang your feet over the end of the bed. This will keep your feet in a relaxed position. It’ll help stop the muscles in your calves from contracting and tensing.

Keep your sheets and blankets loose.

Last updated:
23 October 2023

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