Editing Sleep (section)

{{Short description|Naturally recurring resting state of mind and body}}
{{About|sleep in humans|non-human sleep|Sleep in animals|other uses}}
{{Redirect2|Asleep|Slept|other uses|Asleep (disambiguation)|and|SLEPT analysis}}
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{{Use dmy dates|date=May 2024}}
[[File:Domenico Fetti - Sleeping Girl - WGA7863.jpg|alt=A sleeping girl|thumb|''Sleeping Girl'', [[Domenico Fetti]], {{circa|1615}}]]

'''Sleep''' is a state of reduced mental and physical activity in which [[consciousness]] is altered and certain [[Sensory nervous system|sensory]] activity is inhibited. During sleep, there is a marked decrease in muscle activity and interactions with the surrounding environment. While sleep differs from [[wakefulness]] in terms of the ability to react to [[Stimulus (physiology)|stimuli]], it still involves active [[Human brain|brain]] patterns, making it more reactive than a [[coma]] or [[disorders of consciousness]]<!-- Disorders of consciousness refer to a group of conditions that affect the level or content of consciousness, leading to alterations in wakefulness and awareness. Some examples of disorders of consciousness include coma, vegetative state, minimally conscious state, and locked-in syndrome. -->.<ref>{{Cite web |title=Brain Basics: Understanding Sleep {{!}} National Institute of Neurological Disorders and Stroke |url=https://www.ninds.nih.gov/health-information/public-education/brain-basics/brain-basics-understanding-sleep |access-date=15 February 2023 |website=www.ninds.nih.gov}}</ref>

Sleep occurs in [[sleep cycle|repeating periods]], during which the body alternates between two distinct modes: [[rapid eye movement sleep]] (REM) and [[Non-rapid eye movement sleep|non-REM sleep]]. Although REM stands for "rapid eye movement", this mode of sleep has many other aspects, including virtual [[Rapid eye movement sleep#Muscle|paralysis]] of the body.<ref>{{Cite web |url=https://quantifysleep.com/the-dichotomy-of-sleep-rem-and-non-rem-stages-and-their-impact-on-human-health |title=The Dichotomy Of Sleep: REM And Non-REM Stages, And Their Impact On Human Health |last=Nelson |first=Ryan |date=20 June 2021 |website=Quantify Sleep |access-date=15 July 2023 }}</ref> [[Dream]]s are a succession of images, ideas, emotions, and sensations that usually occur involuntarily in the [[mind]] during certain stages of sleep.

During sleep, most of the [[human body|body's systems]] are in an [[anabolic]] state, helping to restore the [[Immunity (medical)|immune]], [[Nervous system|nervous]], [[Skeleton|skeletal]], and [[Muscular system|muscular]] systems;<ref name="krueger">{{cite journal | vauthors = Krueger JM, Frank MG, Wisor JP, Roy S | title = Sleep function: Toward elucidating an enigma | journal = Sleep Medicine Reviews | volume = 28 | pages = 46–54 | date = August 2016 | pmid = 26447948 | pmc = 4769986 | doi = 10.1016/j.smrv.2015.08.005 |issn=1087-0792}}</ref> these are vital processes that maintain [[Mood (psychology)|mood]], [[memory]], and [[cognitive function]], and play a large role in the function of the [[Endocrine system|endocrine]] and [[immune system]]s.<ref name=":3">{{cite web|date=2006|title=Sleep-wake cycle: its physiology and impact on health|url=https://sleepfoundation.org/sites/default/files/SleepWakeCycle.pdf|publisher=National Sleep Foundation|access-date=24 May 2017|archive-url=https://web.archive.org/web/20170830035939/https://sleepfoundation.org/sites/default/files/SleepWakeCycle.pdf|archive-date=30 August 2017|url-status=live}}</ref> The internal [[circadian clock]] promotes sleep daily at [[night]], when it is dark. The diverse purposes and [[Neuroscience of sleep|mechanisms of sleep]] are the subject of substantial ongoing research.<ref name=":5">{{cite web |url=https://thesciencenetwork.org/programs/waking-up-to-sleep |title=Waking Up To Sleep |access-date=25 January 2008 | vauthors = Bingham R, Terrence S, Siegel J, Dyken ME, Czeisler C |date=February 2007 |format=Several conference videos |publisher=The Science Network |archive-url=https://web.archive.org/web/20110724132410/https://thesciencenetwork.org/programs/waking-up-to-sleep |archive-date=24 July 2011 |url-status=live }}</ref> Sleep is a highly [[Conserved sequence|conserved]] behavior across animal evolution,<ref name=Joiner2016>{{cite journal | vauthors = Joiner WJ | title = Unraveling the Evolutionary Determinants of Sleep | journal = Current Biology | volume = 26 | issue = 20 | pages = R1073–R1087 | date = October 2016 | pmid = 27780049 | pmc = 5120870 | doi = 10.1016/j.cub.2016.08.068 | bibcode = 2016CBio...26R1073J }}</ref> likely going back hundreds of millions of years,<ref name="Keene & Duboue, 2018">{{cite journal | url=https://doi.org/10.1242/jeb.159533 | title=The origins and evolution of sleep. | journal=The Journal of Experimental Biology | date=12 June 2018 | accessdate=10 January 2023 | volume=221 | issue=11 | doi=10.1242/jeb.159533 | pmid=29895581 | pmc=6515771 | bibcode=2018JExpB.221B9533K | last1=Keene | first1=Alex C. | last2=Duboue | first2=Erik R. }}</ref> and originating as a means for the brain to cleanse itself of waste products.<ref name="ntyimes">{{cite news|last=Konnikova|first=Maria|title=Goodnight. Sleep Clean.|url=https://www.nytimes.com/2014/01/12/opinion/sunday/goodnight-sleep-clean.html|newspaper=[[The New York Times]]|accessdate=18 February 2014|date=11 January 2014|quote=She called it the glymphatic system, a nod to its dependence on glial cells}}</ref>  In a major breakthrough, researchers have found that cleansing, including the removal of [[amyloid]], may be a core purpose of sleep.<ref name="science2">{{cite news|last=Coontz|first=Robert|title=Science's Top 10 Breakthroughs of 2013|url=https://www.science.org/content/article/sciences-top-10-breakthroughs-2013|newspaper=[[Science (journal)|Science]]|accessdate=12 January 2025|date=19 December 2013}}</ref>

Humans may suffer from various [[sleep disorder]]s, including [[dyssomnia]]s, such as [[insomnia]], [[hypersomnia]], [[narcolepsy]], and [[sleep apnea]]; [[parasomnia]]s, such as [[sleepwalking]] and [[rapid eye movement sleep behavior disorder]]; [[bruxism]]; and [[circadian rhythm sleep disorder]]s. The use of [[artificial light]] has substantially altered humanity's sleep patterns.<ref>{{cite news| vauthors = Randall DK |title=Book excerpt: How the lightbulb disrupted our sleeping patterns and changed the world|url=https://news.nationalpost.com/full-comment/book-excerpt-how-the-lightbulb-disrupted-our-sleeping-patterns-and-changed-the-world|access-date=31 August 2016|work=National Post|date=19 September 2012|quote="... the sudden introduction of bright nights during hours when it should be dark threw a wrench into a finely choreographed system of life.|archive-url=https://archive.today/20190407032206/https://nationalpost.com/opinion/book-excerpt-how-the-lightbulb-disrupted-our-sleeping-patterns-and-changed-the-world|archive-date=7 April 2019|url-status=live}}</ref> Common sources of artificial light include [[Light pollution#Public health impact|outdoor lighting]] and the screens of digital devices such as [[Smartphone|smartphones]] and [[Television set|televisions]], which emit large amounts of [[Blue light spectrum|blue light]], a form of light typically associated with daytime. This disrupts the release of the hormone [[melatonin]] needed to regulate the [[sleep cycle]].<ref>{{Cite web|date=4 November 2020|title=How Blue Light Affects Sleep|url=https://www.sleepfoundation.org/bedroom-environment/blue-light|access-date=18 November 2021|website=Sleep Foundation|language=en}}</ref>