Sleep cycle - Wikipedia

The sleep cycle is an oscillation between the slow-wave and REM (paradoxical) phases of sleep. It is sometimes called the ultradian sleep cycle, sleep–dream ... Sleepcycle FromWikipedia,thefreeencyclopedia Jumptonavigation Jumptosearch Oscillationbetweenthe slow-wave and REMphasesof sleep Forthealbum,seeSleepCycle. Samplehypnogramshowingonesleepcycle(thefirstofthenight)fromNREMthroughREM Thesleepcycleisanoscillationbetweentheslow-waveandREM(paradoxical)phasesofsleep.Itissometimescalledtheultradiansleepcycle,sleep–dreamcycle,orREM-NREMcycle,todistinguishitfromthecircadianalternationbetweensleepandwakefulness.Inhumans,thiscycletakes70to110minutes(90±20minutes).[1] Contents 1Characteristics 2Length 3Awakening 4Continuationduringwakefulness 5Alteration 6Seealso 7References 7.1Bibliography Characteristics[edit] ElectroencephalographyshowsthetimingofsleepcyclesbyvirtueofthemarkeddistinctioninbrainwavesmanifestedduringREMandnon-REMsleep.Deltawaveactivity,correlatingwithslow-wave(deep)sleep,inparticularshowsregularoscillationsthroughoutagoodnight'ssleep.Secretionsofvarioushormones,includingrenin,growthhormone,andprolactin,correlatepositivelywithdelta-waveactivity,whilesecretionofthyroid-stimulatinghormonecorrelatesinversely.[2]Heartratevariability,wellknowntoincreaseduringREM,predictablyalsocorrelatesinverselywithdelta-waveoscillationsoverthe~90-minutecycle.[3] Inordertodetermineinwhichstageofsleeptheasleepsubjectis,electroencephalographyiscombinedwithotherdevicesusedforthisdifferentiation.EMG(electromyography)isacrucialmethodtodistinguishbetweensleepphases:forexample,adecreaseofmuscletoneisingeneralacharacteristicofthetransitionfromwaketosleep,[4][5]andduringREMsleep,thereisastateofmuscleatonia(paralysis),resultinginanabsenceofsignalsintheEMG.[4] EOG(electrooculography),themeasureoftheeyes’movement,isthethirdmethodusedinthesleeparchitecturemeasurement;[6]forexample,REMsleep,asthenameindicates,ischaracterizedbyarapideyemovementpattern,visiblethankstotheEOG.[7] Moreover,methodsbasedoncardiorespiratoryparametersarealsoeffectiveintheanalysisofsleeparchitecture—iftheyareassociatedwiththeotheraforementionedmeasurements(suchaselectroencephalography,electrooculographyandtheelectromyography).[8] Homeostaticfunctions,especiallythermoregulation,occurnormallyduringnon-REMsleep,butnotduringREMsleep.Thus,duringREMsleep,bodytemperaturetendstodriftawayfromitsmeanlevel,andduringnon-REMsleep,toreturntonormal.Alternationbetweenthestagesthereforemaintainsbodytemperaturewithinanacceptablerange.[9] Inhumans,thetransitionbetweennon-REMandREMisabrupt;inotheranimals,itislessso.[10] ResearchershaveproposeddifferentmodelstoelucidatetheundoubtedlycomplexrhythmofelectrochemicalprocessesthatresultintheregularalternationofREMandNREMsleep.MonoaminesareactiveduringNREMS,butnotREMS,whereasacetylcholineismoreactiveduringREMS.Thereciprocalinteractionmodelproposedinthe1970ssuggestedacyclicgive-and-takebetweenthesetwosystems.Morerecenttheoriessuchasthe"flip-flop"model,proposedinthe2000s,includetheregulatoryroleofaninhibitoryneurotransmittergamma-aminobutyricacid(GABA).[11] Length[edit] Schematicillustrationofanormalsleepcycle Thestandardfiguregivenfortheaveragelengthofthesleepcycleinanadultmanis90minutes.N1(NREMstage1)iswhenthepersonisdrowsyorawaketofallingasleep.Brainwavesandmuscleactivitystarttodecreaseatthisstage.N2iswhenthepersonexperiencesalightsleep.Eyemovementhasstoppedbythistime.Brainwavefrequencyandmuscletonusisdecreased.Theheartrateandbodytemperaturealsogoesdown.N3orevenN4arethemostdifficultstagestobeawakened.Everypartofthebodyisnowrelaxed,breathing,bloodpressureandbodytemperaturearereduced.TheNationalSleepFoundationdiscussesthedifferentstagesofNREMsleepandtheirimportance.TheydescribeREMsleepas"Auniquestate,inwhichdreamsusuallyoccur.Thebrainisawakeandbodyparalyzed."Thisuniquestageusuallyoccurswhenthepersondreams.[12][10]Thefigureof90minutesfortheaveragelengthofasleepcyclewaspopularizedbyNathanielKleitmanaround1963.[13]Othersourcesgive90–110minutes[2]or80–120minutes.[3] ThecaptiveAsianelephant(pictured)isthoughttohaveasleepcycleof72minutes.[14] Ininfants,thesleepcyclelastsabout50–60minutes;averagelengthincreasesasthehumangrowsintoadulthood.Incats,thesleepcyclelastsabout30minutes,thoughitisabout12minutesinratsandupto120minutesinelephants.(Inthisregardtheontogenyofthesleepcycleappearsproportionatewithmetabolicprocesses,whichvaryinproportionwithorganismsize.However,shortersleepcyclesdetectedinsomeelephantscomplicatethistheory.)[10][12][14] ThecyclecanbedefinedaslastingfromtheendofoneREMperiodtotheendofthenext,[12]orfromthebeginningofREM,orfromthebeginningofnon-REMstage2.(Thedecisionofhowtomarktheperiodsmakesadifferenceforresearchpurposes,becauseoftheunavoidableinclusionorexclusionofthenight'sfirstNREMoritsfinalREMphaseifdirectlyprecedingawakening.)[13] A7–8-hoursleepprobablyincludesfivecycles,themiddletwoofwhichtendtobelongerthanthefirstandthefourth.[13]REMtakesupmoreofthecycleasthenightgoeson.[10][15] Awakening[edit] UnprovokedawakeningoccursmostcommonlyduringorafteraperiodofREMsleep,asbodytemperatureisrising.[16] Continuationduringwakefulness[edit] ErnestHartmanndiscoveredin1968thathumansseemtocontinuearoughly90-minuteultradianrhythmthroughouta24-hourday,whethertheyareasleeporawake.[12]Accordingtothishypothesis,duringtheperiodofthiscyclecorrespondingwithREM,peopletendtodaydreammoreandshowlessmuscletone.[17]Kleitmanandothersfollowinghavereferredtothisrhythmasthebasicrest–activitycycle,ofwhichthe"sleepcycle"wouldbeamanifestation.[13][18]Adifficultyforthistheoryisthefactthatalongnon-REMphasealmostalwaysprecedesREM,regardlessofwheninthecycleapersonfallsasleep.[13] Alteration[edit] Thesleepcyclehasprovenresistanttosystematicalterationbydrugs.AlthoughsomedrugsshortenREMperiods,theydonotabolishtheunderlyingrhythm.DeliberateREMdeprivationshortensthecycletemporarily,asthebrainmovesintoREMsleepmorereadily(the"REMrebound")inanapparentcorrectionforthedeprivation.[12]Therearevariousmethodstocontrolthealterationsofsleepcycles: Switchingoffallartificiallights:[19]Sincethenaturalproductionofmelatonincanbesuppressedbybrightlight,exposingtolight—evenaftersunset—[20]maypreventthebodyfromfeelingsleepy(andhenceenteringthesleepphase). Meditationandrelaxationtechniques:[21] Stayingawayfromcaffeinebeforebedtime:[22]Thisensuresthatthebodyisnotunderthestimulanteffectsofcaffeinewhiletryingtosleep. Externalaids:Blue-lightblockinglensandcoveringthebedroomwithblackoutcurtainsorwearinganeyemaskcanhelpwithfallingasleepfasterandfeelingmorerefreshedaftersleep.[citationneeded] Seealso[edit] Biphasicandpolyphasicsleep Circadianrhythm References[edit] ^"WhatHappensDuringSleep?|UPMCSleepMedicineResources".UPMC|LifeChangingMedicine.Retrieved2021-09-24. ^abGronfier,Claude;Simon,Chantal;Piquard,François;Ehrhart,Jean;Brandenberger,Gabrielle(1999)."NeuroendocrineProcessesUnderlyingUltradianSleepRegulationinMan".JournalofClinicalEndocrinology&Metabolism.84(8):2686–2690.doi:10.1210/jcem.84.8.5893.PMID 10443660. ^abBrandenberger,Gabrielle;Erhart,Jean;Piquard,François;Simon,Chantal(2001)."Inversecouplingbetweenultradianoscillationsindeltawaveactivityandheartratevariabilityduringsleep"(PDF).ClinicalNeurophysiology.112(6):992–996.doi:10.1016/S1388-2457(01)00507-7.PMID 11377256.S2CID 206133162.Archivedfromtheoriginal(PDF)on2017-08-04. ^abChase,M.H.;Morales,F.R.(1990)."Theatoniaandmyocloniaofactive(REM)sleep".AnnualReviewofPsychology.41(1):557–584.doi:10.1146/annurev.ps.41.020190.003013.PMID 1968326. ^Kleitman,N.(1963).SleepandWakefulnessChicago,Univ.ChicagoJfress ^Berry,R.B.,&Wagner,M.H.(2014).SleepMedicinePearlsE-Book.ElsevierHealthSciences. ^berC.,Ancoli-IsraelS.,ChessonA.,andQuanSF.inTheAASMManualfortheScoringofSleepandAssociatedEvents:Rules,TerminologyandTechnicalSpecifications,1st.Ed.:Westchester,Illinois:AmericanAcademyofSleepMedicine;2007. ^Tataraidze,A.,Korostovtseva,L.,Anishchenko,L.,Bochkarev,M.,&Sviryaev,Y.(2016,).Sleeparchitecturemeasurementbasedoncardiorespiratoryparameters. ^PierLuigiParmeggiani,"ModulationofbodycoretemperatureinNREMsleepandREMsleep";inMallicketal.(2011). ^abcdMcCarley,RobertW.(2007)."NeurobiologyofREMandNREMsleep".SleepMedicine.8(4):302–330.doi:10.1016/j.sleep.2007.03.005.PMID 17468046. ^JamesT.McKenna,LichaoChen,&RobertMcCarley,"NeuronalmodelsofREM-sleepcontrol:evolvingconcepts";inMallicketal.(2011). ^abcdeHartmann,Ernest(March1968)."The90-MinuteSleep-DreamCycle".ArchivesofGeneralPsychiatry.18(3):280–6.doi:10.1001/archpsyc.1968.01740030024004.PMID 5638533. ^abcdeFeinberg,I.;Floyd,T.C.(1979)."SystematicTrendsAcrosstheNightinHumanSleepCycles".Psychophysiology.16(3):283–291.doi:10.1111/j.1469-8986.1979.tb02991.x.PMID 220659. ^abTobler,Irene(1992)."BehavioralsleepintheAsianelephantincaptivity".Sleep.15(1):1–12.PMID 1557589. ^DanielAeschbach,"REM-sleepregulation:circadian,homeostatic,andnon-REMsleep-dependentdeterminants";inMallicketal.(2011). ^Åkerstedt,Torbjorn;Billiard,Michel;Bonnet,Michael;Ficca,Gianluca;Garma,Lucile;Mariotti,Maurizio;Salzarulo,Piero;Schulz,Hartmut(2002)."Awakeningfromsleep"(PDF).SleepMedicineReviews.6(4):267–286.doi:10.1053/smrv.2001.0202.PMID 12531132. ^EkkehardOthmer,MaryP.Hayden,andRobertSegelbaum,"EncephalicCyclesduringSleepandWakefulnessinHumans:a24-HourPattern"(JSTOR);Science164(3878),25April1969. ^Kleitman,Nathaniel(1982)."BasicRest-ActivityCycle—22YearsLater".Sleep.5(4):311–317.doi:10.1093/sleep/5.4.311.PMID 6819628. ^Blume,Christine;Garbazza,Corrado;Spitschan,Manuel(2019)."Effectsoflightonhumancircadianrhythms,sleepandmood".Somnologie.23(3):147–156.doi:10.1007/s11818-019-00215-x.PMC 6751071.PMID 31534436. ^L,Tähkämö;T,Partonen;Ak,Pesonen(2019)."SystematicReviewofLightExposureImpactonHumanCircadianRhythm".ChronobiologyInternational.36(2):151–170.doi:10.1080/07420528.2018.1527773.PMID 30311830.S2CID 52960410. ^P,Spagnoli;C,Balducci;M,Fabbri;D,Molinaro;G,Barbato(20September2019)."Workaholism,IntensiveSmartphoneUse,andtheSleep-WakeCycle:AMultipleMediationAnalysis".InternationalJournalofEnvironmentalResearchandPublicHealth.16(19):3517.doi:10.3390/ijerph16193517.PMC 6801767.PMID 31547191. ^Jr,Anderson;Pl,Hagerdorn;J,Gunstad;Mb,Spitznagel(2018)."UsingCoffeetoCompensateforPoorSleep:ImpactonVigilanceandImplicationsforWorkplacePerformance".AppliedErgonomics.70:142–147.doi:10.1016/j.apergo.2018.02.026.PMID 29866304. Bibliography[edit] Mallick,B.N.;S.R.Pandi-Perumal;RobertW.McCarley;andAdrianR.Morrison(2011).RapidEyeMovementSleep:RegulationandFunction.CambridgeUniversityPress.ISBN 978-0-521-11680-0 Nir,andTononi,"DreamingandtheBrain:fromPhenomenologytoNeurophsiology."TrendsinCognitiveSciences,vol.14,no.2,2010,pp. 88–100. Varela,F.,Engel,J.,Wallace,B.,&ThuptenJinpa.(1997).Sleeping,dreaming,anddying:AnexplorationofconsciousnesswiththeDalaiLama. 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