Slp s stt f rdcd mntl nd physcl ctvty n whch cnscsnss s ltrd nd crtn snsry ctvty s nhbtd. Drng slp, thr s mrkd dcrs n mscl ctvty nd ntrctns wth th srrndng nvrnmnt. Whl slp dffrs frm wkflnss n trms f th blty t rct t stml, t stll nvlvs ctv brn pttrns, mkng t mr rctv thn cm r dsrdrs f cnscsnss.
Slp ccrs n rptng prds, drng whch th bdy ltrnts btwn tw dstnct mds: rpd y mvmnt slp (RM) nd nn-RM slp. lthgh RM stnds fr "rpd y mvmnt", ths md f slp hs mny thr spcts, ncldng vrtl prlyss f th bdy. Drms r sccssn f mgs, ds, mtns, nd snstns tht slly ccr nvlntrly n th mnd drng crtn stgs f slp.
Drng slp, mst f th bdy's systms r n n nblc stt, hlpng t rstr th mmn, nrvs, skltl, nd msclr systms; ths r vtl prcsss tht mntn md, mmry, nd cgntv fnctn, nd ply lrg rl n th fnctn f th ndcrn nd mmn systms. Th ntrnl crcdn clck prmts slp dly t nght, whn t s drk. Th dvrs prpss nd mchnsms f slp r th sbjct f sbstntl ngng rsrch. Slp s hghly cnsrvd bhvr crss nml vltn, lkly gng bck hndrds f mllns f yrs, nd rgntng s mns fr th brn t clns tslf f wst prdcts. n mjr brkthrgh, rsrchrs hv fnd tht clnsng, ncldng th rmvl f myld, my b cr prps f slp.
Hmns my sffr frm vrs slp dsrdrs, ncldng dyssmns, sch s nsmn, hyprsmn, nrclpsy, nd slp pn; prsmns, sch s slpwlkng nd rpd y mvmnt slp bhvr dsrdr; brxsm; nd crcdn rhythm slp dsrdrs. Th s f rtfcl lght hs sbstntlly ltrd hmnty's slp pttrns. Cmmn srcs f rtfcl lght ncld tdr lghtng nd th scrns f lctrnc dvcs sch s smrtphns nd tlvsns, whch mt lrg mnts f bl lght, frm f lght typclly ssctd wth dytm. Ths dsrpts th rls f th hrmn mltnn ndd t rglt th slp cycl.