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

Example Sentences

Recent Examples on the Web

Review your medications Some medications can prompt nightmares by interrupting REM sleep. —Kristen Rogers, CNN, 14 Apr. 2023

Scientists say humans have their most vivid dreams during REM sleep. —Julian Mark, Washington Post, 15 Aug. 2022

Excessive alcohol, which the body must process during the night, will actually cause fragmented sleep — which disturbs REM sleep. —Fox News, 27 June 2022

Stage 4 is REM sleep. —Bryant Stamford, The Courier-Journal, 19 May 2022

McGillivray’s Marathon Monday starts at Copley Square at 4:20 a.m., after not much REM sleep. —Globe Staff, BostonGlobe.com, 19 Apr. 2022

Research has found that depriving someone of REM sleep—the sleep stage in which most dreams occur—might account for the health problems associated with sleep loss. —Michael W. Clune, Harper’s Magazine , 16 Mar. 2022

In later parts of the sleep cycle, or non-REM stage 3 and REM sleep, sleep talking usually sounds more like moaning and groaning, according to the National Sleep Foundation. —Haley Goldberg, SELF, 29 Dec. 2021

In a 2018 study published in Frontiers in Psychology, brown noise was also shown to support the transition into REM sleep for some. —Marisa Sloan, Discover Magazine, 27 Mar. 2023

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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