The chief symptom is an urge to move the legs. Common accompanying characteristics of RLS/WED include:

• Sensations that begin after rest. The sensation typically begins after you've been lying down or sitting for an extended time, such as in a car, airplane or movie theater.
• Relief with movement. The sensation of RLS/WED lessens with movement, such as stretching, jiggling your legs, pacing or walking.
• Worsening of symptoms in the evening. Symptoms occur mainly at night.
• Nighttime leg twitching. RLS/WED may be associated with another, more common condition called periodic limb movement of sleep, which causes your legs to twitch and kick, possibly throughout the night, while you sleep.

People typically describe RLS/WED symptoms as abnormal, unpleasant sensations in their legs or feet. They usually happen on both sides of the body. Less commonly, the sensations affect the arms.

The sensations, which generally occur within the limb rather than on the skin, are described as:

• Crawling
• Creeping
• Pulling
• Throbbing
• Aching
• Itching
• Electric

Sometimes the sensations are difficult to explain. Affected people usually don't describe the condition as a muscle cramp or numbness. They do, however, consistently describe the desire to move their legs.

It's common for symptoms to fluctuate in severity. Sometimes, symptoms disappear for periods of time, then come back.

Often, there's no known cause for RLS/WED. Researchers suspect the condition may be caused by an imbalance of the brain chemical dopamine, which sends messages to control muscle movement.

Heredity

Sometimes RLS/WED runs in families, especially if the condition starts before age 40. Researchers have identified sites on the chromosomes where genes for RLS/WED may be present.

Pregnancy

Pregnancy or hormonal changes may temporarily worsen RLS/WED signs and symptoms. Some women get RLS/WED for the first time during pregnancy, especially during their last trimester. However, signs and symptoms usually disappear after delivery.

RLS/WED can develop at any age, even during childhood. The disorder is more common with increasing age and more common in women than in men.

Restless legs syndrome usually isn't related to a serious underlying medical problem. However, RLS/WED sometimes accompanies other conditions, such as:

• Peripheral neuropathy. This damage to the nerves in your hands and feet is sometimes due to chronic diseases such as diabetes and alcoholism.
• Iron deficiency. Even without anemia, iron deficiency can cause or worsen RLS/WED. If you have a history of bleeding from your stomach or bowels, experience heavy menstrual periods, or repeatedly donate blood, you may have iron deficiency.
• Kidney failure. If you have kidney failure, you may also have iron deficiency, often with anemia. When kidneys don't function properly, iron stores in your blood can decrease. This and other changes in body chemistry may cause or worsen RLS/WED.
• Spinal cord conditions. Lesions on the spinal cord have been linked to RLS/WED. Having had anesthesia to the spinal cord, such as a spinal block, also increases the risk of developing RLS/WED.

Although RLS/WED doesn't lead to other serious conditions, symptoms can range from barely bothersome to incapacitating. Many people with RLS/WED find it difficult to fall or stay asleep.

Severe RLS/WED can cause marked impairment in life quality and can result in depression. Insomnia may lead to excessive daytime drowsiness, but RLS/WED may interfere with napping.