rapid eye movement

Definition of rapid eye movement sleep

rapid eye movement sleep

(RA-pid I MOOV-ment sleep)
The phase of sleep in which most dreams occur. During rapid eye movement sleep, a person’s brain activity, breathing, heart rate, and blood pressure increase, and the eyes move rapidly while closed. The muscles in the arms and legs become temporarily unable to move. Rapid eye movement sleep is thought to play an important role in memory and learning. During normal sleep, a person goes through four to five sleep cycles that last about 90 minutes each and include both rapid eye movement sleep and non-rapid eye movement sleep (light to deep sleep). Also called REM sleep.

Source: NCI Dictionary of Cancer Terms