Leg cramps are a common and usually harmless condition in which the muscles in your leg suddenly become tight and painful. It usually occurs in the calf muscles, although it can affect any part of your leg, including your feet and thighs.
During a cramp, your muscles suddenly contract (shorten), causing pain in your leg. This is known as a spasm, and you cannot control the affected muscle. 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.
After the cramping has passed, you may have pain and tenderness in your leg for several hours. Three out of four cases occur at night during sleep.
What causes leg cramps?
Leg cramps can occur for no apparent reason (idiopathic leg cramps). Leg cramps can also occur as a symptom or complication of a health condition—this is known as secondary leg cramps. Causes of secondary leg cramps can include:
- Certain types of medication, such as statins (medicines that help lower cholesterol levels)
- Liver disease
When to seek medical advice
If you only get leg cramps occasionally, it is not a cause for concern and a medical diagnosis is not required.
A visit to your doctor will only be necessary if you get leg cramps frequently, or if they are so painful they disrupt your sleep and you are unable to function normally the next day.
You should also visit your doctor if the muscles in your legs are shrinking or becoming weaker.
When to seek immediate medical care
There are two situations where leg cramps may be a sign of a more serious underlying health condition. You should seek immediate medical help if:
- The cramps last longer than 10 minutes and fail to improve, despite exercise.
- Cramps develop after you come into contact with substances that could be toxic (poisonous) or infectious, for example, if you have a cut that is contaminated with soil, which can sometimes cause a bacterial infection, such as tetanus, or after being exposed to elements such as mercury or lead.
Your doctor will ask about your symptoms and examine your legs and feet. They may also ask if you have other symptoms, such as numbness or swelling, which may be a sign that you have secondary leg cramps caused by an underlying condition.
In this case, you may need further tests, such as blood tests and urine tests, to rule out other conditions.
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, stand with the front half of your feet on a step, with your heels hanging off the edge. Slowly lower your heels so that they are below the level of the step. Hold for a few seconds before lifting your heels back up to the starting position. Repeat a number of times.
Medication is usually only needed in the most 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 such as muscle relaxants.