Restless legs syndrome

Restless legs syndrome, also called Willis-Ekbom disease, is a movement disorder, and it's chronic, meaning it lasts a long time. People who have it feel an irresistible urge to move their legs, and that urge comes with uncomfortable sensations in the legs. It shows up when the legs are at rest, and moving them brings relief. Think of it as an alarm that goes off when the body settles down, then quiets as soon as the legs start moving.

So why does it happen? It still isn't fully understood, but what researchers have found points to the inside of the brain. One piece of the puzzle is dopamine, a chemical messenger the brain uses to make movements smooth and purposeful. The syndrome has been linked to problems in the dopaminergic system, the network of nerve cells that communicate using dopamine. The other piece is iron: some areas of the brain, such as the substantia nigra and the thalamus, have been found to have low levels of it.

The symptoms get stronger at night. And most people with restless legs also have periodic limb movements of sleep: while they're asleep, their legs jerk involuntarily, which means the movements happen on their own, without the person choosing to make them.