What Is Restless Leg Syndrome?

Medical Author: Melissa Stoppler, M.D.
Medical Editor: Barbara K. Hecht, Ph.D.

Restless leg syndrome (RLS), also known as nocturnal myoclonus, is a type of sleep disorder characterized by uncomfortable sensations in the legs and an uncontrollable desire to move the legs. These abnormal sensations usually occur in the lower legs shortly after going to bed. During the early stages of sleep, these episodes of leg movement often last up to an hour.

The abnormal sensations of RLS are quite variable. They have been described as a crawling, creeping, pulling, drawing, tingling, pins and needles, or prickly discomfort. They are not cramping in character.

Sometimes these sensations occur in the feet, thighs or even arms. Although RLS is considered to be a sleep disorder, some people also experience these sensations during the day, particularly when lying down.

The most important feature of RLS is an overwhelming need to move the legs. Moving the legs provides temporary relief but the abnormal sensations start all over again and the cycle repeats itself.

While the cause of RLS is unknown, it does tend to occur in association with a number of chronic conditions including iron deficiency anemia, obesity, diabetes, diseases of the peripheral nerves, and kidney failure. However, many persons with RLS will not have any identifiable predisposing disease or condition.