Leg cramps are a common, annoying but usually harmless condition that cause sudden muscle pain in the leg. Leg cramps usually occur in the calf muscles below the knee, although they can affect any part of the leg.
In three out of four cases, leg cramps occur at night during sleep.
What are cramps?
A leg cramp occurs when your muscles suddenly shorten (contract), causing pain in your leg. This is called a spasm. You cannot control the affected muscle when it happens.
The cramp can last from a few seconds to 10 minutes. When the spasm passes, you will be able to control the affected muscle again.
Types of leg cramps
There are two main types of leg cramps:
- idiopathic leg cramps occur for no apparent reason (idiopathic is a Greek word that roughly translates as ‘suffering for no reason’)
- secondary leg cramps are a symptom or complication of a known health condition
Causes of secondary leg cramps include:
See Leg cramps – causes for more information about the possible causes of secondary leg cramps.
How common are leg cramps?
It is difficult to estimate exactly how commonly leg cramps occur because most people do not report their symptoms to their GP.
From what evidence is available, it seems that two groups of people are particularly affected by leg cramps:
- older adults over 60 years old – it is thought that one third of people over 60 experience leg cramps, with 40% of these people having three or more cramps a week
- pregnant women – it is estimated that a third of pregnant women have leg cramps, usually during the last trimester of pregnancy (from week 27 to the birth)
However, people of all ages, including children, have reported idiopathic leg cramps.
There does not appear to be any difference in the rates of men or women affected by leg cramps.
Outlook
In most cases, cramping can be relieved by exercising the affected muscles. Regularly exercising during the day often helps to reduce the frequency of cramping episodes.
Medication is usually only required for the most persistent cases of cramping that do not respond to exercise.
For more information on exercise and medication, see Leg cramps – treatment.
The outlook for secondary leg cramps will depend on the underlying cause. For example, leg cramps that occur during pregnancy should pass once the baby is born.
Leg cramps that occur during a serious case of liver disease can be harder to treat. They may require a more aggressive treatment approach, with medications such as muscle relaxants.
