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 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'REM sleep.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1963, in the meaning defined above

Time Traveler
The first known use of REM sleep was in 1963

Dictionary Entries Near REM sleep

Cite this Entry

“REM sleep.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/REM%20sleep. Accessed 28 May. 2023.

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
Last Updated: - Updated example sentences
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