Definition

Nocturnal leg cramps are sudden spasms in the lower leg and foot muscles. The calf muscles are most often involved. The cramps are painful and often disrupt sleep.

The Calf Muscles Copyright © Nucleus Medical Media, Inc.

Causes

The exact cause of nocturnal leg cramps is unknown. They may be due to chemical imbalances. This may lead to problems with the nerves, muscles, or blood supply.

Risk Factors

Nocturnal leg cramps are more common in people aged 50 years and older. Other things that raise the risk are:

• Pregnancy
• Alcohol use disorder
• Overusing muscles
• Prolonged sitting, or standing on hard surfaces
• Flat feet, or other foot or ankle deformities
• Certain medicines such as those to treat high blood pressure and high cholesterol
• Certain health conditions, such as:
  • Diseases of the liver, kidneys, heart, and blood vessels
  • Cancer
  • Hormone disorders—such as thyroid disorders or diabetes
  • Neurological disorders—such as Parkinson disease and peripheral neuropathy
  • Imbalances in minerals—such as calcium, potassium, and magnesium
  • Dehydration

Symptoms

The main symptom is a sudden cramp in the calf or foot muscle.

Diagnosis

The doctor will ask about symptoms and health history. A physical exam will be done. Diagnosis is based on symptoms.

Blood tests and imaging tests may be done to check for underlying causes.

Treatment

The goal of treatment is to reduce cramps. It may also include treating any underlying causes.

If no cause is found, treatment options are:

• Stretching leg muscles—when cramps occur
• Standing on the affected leg and walking—to help stop cramping
• Massage, and hot or cold treatments—to relax the muscles

Prevention

The risk of nocturnal leg cramps may be reduced by:

• Exercising and stretching the legs and feet
• Drinking plenty of liquids
• Wearing comfortable, supportive shoes