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
Recent Examples on the Web
According to a study from the Journal of Physiological Anthropology, heat exposure increases wakefulness and decreases time spent in deep sleep and REM sleep.
—Nicole Kinning, WIRED, 21 Nov. 2024
Goswami explained that when people are in a deep REM sleep, the heart gets a chance to relax.
—Nicole Villalpando, Austin American-Statesman, 21 Oct. 2024
Nightmares, on the other hand, are concentrated in the second half of the night during REM sleep.
—Lori Miller Kase, Parents, 30 Oct. 2024
Regularly occurring bouts of retinal movements suggest an REM sleep–like state in jumping spiders
Washington State University.
—Jake Parks, Discover Magazine, 14 Oct. 2024
See all Example Sentences for REM sleep 
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Nicole Kinning, WIRED, 21 Nov. 2024
Goswami explained that when people are in a deep REM sleep, the heart gets a chance to relax.
—Nicole Villalpando, Austin American-Statesman, 21 Oct. 2024
Nightmares, on the other hand, are concentrated in the second half of the night during REM sleep.
—Lori Miller Kase, Parents, 30 Oct. 2024
Regularly occurring bouts of retinal movements suggest an REM sleep–like state in jumping spiders
Washington State University.
—Jake Parks, Discover Magazine, 14 Oct. 2024
See all Example Sentences for REM sleep
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 1 Dec. 2024.
Copy CitationMedical 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
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?
Merriam-Webster unabridged
Share