Nocturnal Leg Cramps: Why Do They Happen?

By Wendy Innes. May 7th 2016

Many people experience nighttime leg cramps with varying frequency and for various reasons. Recently, treatment guidelines for leg cramps have changed, but this doesn't mean that people have to suffer in silence.

Why Do They Happen?

Nocturnal leg cramps, also known as a "charley horse", are defined as a sudden and painful involuntary contraction of one or more of the muscles in the legs. These cramps can occur for a variety of reasons. Typically they affect the calf muscles, but they can affect any of the muscles in one or both legs. In most cases, night time leg cramps are relatively harmless, although the sharp pain they cause can be quite discomforting.

Here is a list of possible causes:


  • Blood pressure medications
  • Cholesterol medications
  • Oral contraceptives
  • Diuretics (these flush fluid from the body)
  • Lithium
  • Morphine

Structural Problems

  • Spinal Stenosis (a narrowing of the spinal column that puts pressure on the spinal cord)
  • Peripheral Artery Disease (PAD)
  • Flat feet

Metabolic Problems

  • Diabetes (both type 1 and type 2)
  • Addison's disease
  • Alcoholism
  • Hypothyroidism (under-active thyroid)
  • Cirrhosis
  • Kidney Failure

Other Common Causes

  • Pregnancy
  • Dehydration
  • Diarrhea
  • Muscle fatigue
  • Parkinson's disease
  • Prolonged sitting
  • Standing on a hard surface
  • Certain leg positions when sedentary

Who Gets Them?

Anyone can get them, from a small child to an elderly person. However, there are some people who are more prone to getting nocturnal leg cramps. The risk factors include;

  • Age: though leg cramps can happen at any age, they are more common in people over the age of 50. Both men and women are affected equally.
  • Pregnancy: the changes that occur in a woman's body during pregnancy can cause leg cramps, especially in the later stages, when there is more strain on the body.
  • Foot or ankle deformities: this includes flat feet and other problems as well as those who have sustained a major injury to their foot or ankle in the past, even if healed properly. These problems can put increased strain on the lower leg muscles.
  • Alcoholism: alcoholism wreaks havoc on the human body and can cause leg cramps by causing dehydration and mineral deficiencies.
  • Certain medical conditions: some medical conditions and the treatment for those conditions can cause leg cramps.
  • Activity: overexertion of muscles is a major cause of leg cramps and is common in competitive athletes after the intense exertion of a competition.

Restless Leg Syndrome VS Nocturnal Leg Cramps

While people who have restless leg syndrome, or RLS for short, may experience nocturnal leg cramps, they are two different medical conditions.

The main difference between these two types of nighttime leg disturbances is that pain and cramping is not usually associated with RLS. RLS is characterized by a crawling sensation or the overwhelming need to move the legs in the night. With nighttime leg cramps, the knotted muscle often is difficult to move and quite painful and must be actively manipulated or stretched to find relief.

Treating And Preventing Leg Cramps

Treatment for nighttime leg cramps has changed recently. In the past, those who were troubled by leg cramps were prescribed Quinine, but Quinine comes with some risks and many people have a serious reaction to it, so it is not used much anymore.

Here are some home treatments that can be used to relieve pain from a nocturnal leg cramp:

  • Stretching the leg muscles gently
  • Massaging the cramp
  • Walking or jiggling the leg
  • Ice or heat may be applied

To prevent nocturnal leg cramps:

  • Drink plenty of water during the day to prevent dehydration (this is a very common cause of leg cramps).
  • Wear shoes that are supportive and appropriate for a person's daily activities.
  • Untuck the covers at the foot of the bed to keep from putting pressure on the feet and legs.
  • Stretch leg muscles a few minutes before bed.
  • Eat foods that are rich in potassium since there is a link between low potassium levels and leg cramps. These include bananas, broccoli, cantaloupe, oranges, tomatoes, potatoes and grapefruit.

If nocturnal leg cramps become persistent, then it's best to consult a doctor; these leg cramps may be a sign of a bigger problem. If a person experiences the following, he should talk to his doctor:

  • Muscle weakness or atrophy with the cramps
  • Trouble functioning during the day because of persistently interrupted sleep
  • The cramps develop after being exposed to a toxic substance
  • The cramps are severe and develop suddenly

Most of the time nighttime leg cramps are merely bothersome and nothing to really be concerned about, but it's always best to err on the side of caution. A simple consultation with a doctor can help resolve any ongoing issues with nocturnal leg cramps.


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