REM sleep

noun

: a state of sleep that recurs cyclically with non-REM sleep several times during a normal period of sleep, is characterized especially by greatly depressed muscle tone, dreaming with vivid imagery, rapid eye movements, and increased neuronal activity in certain brain regions (such as the pons), and typically comprises up to 25% of time spent in sleep

REM sleep, it soon became apparent, occurs in intervals throughout the night, usually four to six times, each lasting from ten minutes to an hour.

—Martin Gardner

People awakened during REM sleep usually report dreams with visual images and storylike narratives.

—Lis Harris

called also paradoxical sleep, rapid eye movement sleep

compare slow-wave sleep, non-REM sleep

Examples of REM sleep in a Sentence

Recent Examples on the Web

Rather, people may experience a loss of the sense of smell, constipation, and sleep disturbances known as REM sleep behavior disorder. —Jeffrey Kluger, TIME, 9 July 2024

There is, however, preliminary evidence of another group being more likely to have NDEs: those who are prone to REM sleep intrusion, a condition that occurs when rapid eye movement (REM) sleep intrudes into wakefulness and blends elements of dreaming and waking. —Rachel Nuwer, Scientific American, 14 May 2024

Fitbits with heart rate monitors can discern between light sleep, deep sleep, and REM sleep, when vivid dreams are more likely. —David Nield, WIRED, 4 May 2024

Yet one emerging theory is that the fantastical dreams experienced during REM sleep tame emotions attached to memories and help people gain a broader understanding of what happens to them. —Ingrid Wickelgren, Scientific American, 20 Feb. 2024

Word History

First Known Use

1963, in the meaning defined above

Medical Definition

REM sleep

noun

: a state of sleep that recurs cyclically with non-REM sleep several times during a normal period of sleep, is characterized especially by greatly depressed muscle tone, dreaming with vivid imagery, rapid eye movements, and increased neuronal activity in certain brain regions (as the pons), and typically comprises up to 25% of time spent in sleep

REM sleep, it soon became apparent, occurs in intervals throughout the night, usually four to six times, each lasting from ten minutes to an hour.

—Martin Gardner

People awakened during REM sleep usually report dreams with visual images and storylike narratives.

—Lis Harris

called also desynchronized sleep, paradoxical sleep, rapid eye movement sleep

compare non-rem sleep