Rapid Eye Movement

Rapid eye movement (REM) sleep is a normal stage of sleep characterized by the rapid movement of the eyes. Dreams occur during REM sleep. We typically have 3 to 5 periods of REM sleep per night. They occur at intervals of 1-2 hours and are quite variable in length (short at the beginning of the night and longer toward the end). REM sleep in adults typically occupies 20–25% of total sleep, about 90–120 minutes of a night's sleep.

REM sleep is characterized by a number of other features including rapid, low-voltage brain waves detectable on the electroencephalographic (EEG) recording, irregular breathing and heart rate and involuntary muscle jerks.