Restless legs syndrome
When the urge to move your legs while resting becomes irresistible. It gets worse in the evening and goes away when you move.
A little more detail
Also known as Willis Ekbom disease. It is defined by an urge to move one or both legs (sometimes the arms) while at rest; the urge often comes with unpleasant sensations, is relieved by movement and becomes marked in the evening or at night. The IRLSSG 2014 criteria added, as a fifth essential criterion, that the symptoms are not confused with another condition such as cramps or positional discomfort, and merged the criteria for children with those for adults. Brain iron deficiency and heredity play a part; the AASM 2025 guideline emphasises checking iron levels before treatment.
Source: Allen RP, Picchietti DL, Garcia-Borreguero D et al. Restless legs syndrome/Willis-Ekbom disease diagnostic criteria: updated International Restless Legs Syndrome Study Group (IRLSSG) consensus criteria. Sleep Med. 2014;15(8):860-873. doi:10.1016/j.sleep.2014.03.025; Winkelman JW, Berkowski JA, DelRosso LM et al. Treatment of restless legs syndrome and periodic limb movement disorder: an American Academy of Sleep Medicine clinical practice guideline. J Clin Sleep Med. 2025;21(1):137-152. doi:10.5664/jcsm.11390