Restless legs syndrome (RLS) is a neurological disorder characterized by a constant urge to move the legs (or, more rarely, other body parts like the arms, torso or even phantom limbs) in order to stop uncomfortable or odd sensations. These sensations, typically in the lower legs, are experienced when relaxing, especially on going to bed (but before sleep itself starts), and may last up to an hour in total. Moving the body part usually provides relief, but only temporarily, and the sensations usually start up again almost immediately. Frustratingly, the more the sufferer tries to relax and ignore the symptoms, the worse it gets.
The sensations, which may be a pain or ache, but are more often described as an itching, tickling, tingling or “crawling” sensation, usually begin while relaxing (especially in the evening) or while preparing to sleep. The almost irresistible urge to move the legs and the resulting inability to remain at rest, can result in severe sleep disturbance. To make matters worse, the disorder is also usually accompanied by limb twitching or jerking during sleep (known as periodic limb movement disorder), which can lead to further sleep disruption.
As with most conditions, restless legs syndrome can vary in its severity, ranging from a minor annoyance to a severe disruption causing significant impairment to quality of life. In moderate and severe cases, the symptoms are present almost every night. The condition often starts early in adulthood and gets worse with age, but it is most common in people over 40. By some estimates, as many as 10%-15% of adults are affected by at least some level of the condition, although only 2%-5% seriously. It is almost twice as common in women as men.
RLS is largely genetic in provenance, and a gene marker has recently been discovered which might explain why it tends to run in families. It has been associated with low levels of iron and the neurotransmitter dopamine in the brain. There also appears to be some association with periodic limb movement disorder (PLMD) (a similiar complaint in which, unlike RLS, limb movement occurs involuntarily during sleep), and some 80% of RLS sufferers also report PLMD (although the reverse association is much weaker). Both PLMD and RLS are much more common in older people, affecting up to a third of all over-60s by some estimates. The two disorders are often talked about together and conflated, although they are quite distinct and separate complaints.
Moving the legs, or walking around, brings immediate but only temporary relief from the symptoms, and long-term treatment mainly revolves around oral iron supplements, dopamine agonists (similar to those used to treat Parkinson’s Disease) or relaxants like opioids or cannabis. Nutritional treatments – increasing foods high in iron and magnesium, as well as calcium, potassium and vitamin E, and minimizing the intake of refined sugars, soft drinks and caffeine – often prove quite effective in the long run, and regular exercise may also help.