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
Martin GardnerPeople awakened during REM sleep usually report dreams with visual images and storylike narratives.—Lis Harris
Lis Harriscalled also paradoxical sleep, rapid eye movement sleep
compare slow-wave sleep, non-REM sleepExamples of REM sleep in a Sentence
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The Index tracks a bunch of metrics, including sleep duration, sleep stages (light, deep, and REM sleep), heart rate, blood oxygen saturation, breathing variations, and skin temperature changes.
—Abhimanyu Ghoshal, New Atlas, 19 June 2025
Summer barbecues and partying come with more alcohol, when disrupt REM sleep.
—Jesse Pines, Forbes.com, 12 June 2025
Following deep sleep, REM sleep is the next critical phase of sleep cycles, characterized by more dreaming that’s also extra vivid and lifelike, and by faster heart rate and breathing.
—Kristen Rogers, CNN Money, 8 June 2025
In the REM sleep period, the most memorable and vivid dreams occur.
—Dan Perry, Newsweek, 28 Feb. 2025
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Abhimanyu Ghoshal, New Atlas, 19 June 2025
Summer barbecues and partying come with more alcohol, when disrupt REM sleep.
—Jesse Pines, Forbes.com, 12 June 2025
Following deep sleep, REM sleep is the next critical phase of sleep cycles, characterized by more dreaming that’s also extra vivid and lifelike, and by faster heart rate and breathing.
—Kristen Rogers, CNN Money, 8 June 2025
In the REM sleep period, the most memorable and vivid dreams occur.
—Dan Perry, Newsweek, 28 Feb. 2025
See All Example Sentences for REM sleep
Cite this Entry
“REM sleep.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/REM%20sleep. Accessed 28 Jun. 2025.
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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
Martin GardnerPeople awakened during REM sleep usually report dreams with visual images and storylike narratives.—Lis Harris
Lis Harriscalled also desynchronized sleep, paradoxical sleep, rapid eye movement sleep
compare non-rem sleepLove words? Need even more definitions?
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