Restless legs syndrome (RLS) is characterized by an urge to move the legs. The symptoms are more intense in the evening and during periods of inactivity. RLS symptoms are relieved by movement. It is classified as a sleep disorder, but in many ways it is actually a disorder of wakefulness that seems to intrude upon the ability to transition from wakefulness into sleep. Estimates on prevalence vary according to the methodology employed, but it generally affects between 3.9% and 14.3% of the population.(1) About one-third of persons are affected seriously enough to warrant treatment.(2.)