Editing Sleep (section)

=== Quality ===
The quality of sleep may be evaluated from an objective and a subjective point of view. Objective sleep quality refers to how difficult it is for a person to fall asleep and remain in a sleeping state, and how many times they wake up during a single night. Poor sleep quality disrupts the cycle of transition between the different stages of sleep.<ref>{{cite journal | vauthors = Barnes CM, Lucianetti L, Bhave DP, Christian MS |year=2015 |title=You wouldn't like me when I'm sleepy: Leaders' sleep, daily abusive supervision, and work unit engagement |journal=Academy of Management Journal |volume=58 |issue=5 |pages=1419–1437 |doi=10.5465/amj.2013.1063 |s2cid=145056840 |url=https://ink.library.smu.edu.sg/lkcsb_research/4353 }}</ref> Subjective sleep quality in turn refers to a sense of being rested and regenerated after awaking from sleep. A study by A. Harvey et al. (2002) found that insomniacs were more demanding in their evaluations of sleep quality than individuals who had no sleep problems.<ref>{{cite journal | vauthors = Harvey AG, Payne S | title = The management of unwanted pre-sleep thoughts in insomnia: distraction with imagery versus general distraction | journal = Behaviour Research and Therapy | volume = 40 | issue = 3 | pages = 267–77 | date = March 2002 | pmid = 11863237 | doi = 10.1016/s0005-7967(01)00012-2 | s2cid = 16647017 }}</ref>

Homeostatic sleep propensity (the need for sleep as a function of the amount of time elapsed since the last adequate sleep episode) must be balanced against the circadian element for satisfactory sleep.<ref name="Zisapel">{{cite journal | vauthors = Zisapel N | title = Sleep and sleep disturbances: biological basis and clinical implications | journal = Cellular and Molecular Life Sciences | volume = 64 | issue = 10 | pages = 1174–86 | date = May 2007 | pmid = 17364142 | doi = 10.1007/s00018-007-6529-9 | s2cid = 2003308 | pmc = 11136060 }}</ref><ref>{{cite journal | vauthors = Dijk DJ, Lockley SW | title = Integration of human sleep-wake regulation and circadian rhythmicity | journal = Journal of Applied Physiology | volume = 92 | issue = 2 | pages = 852–62 | date = February 2002 | pmid = 11796701 | doi = 10.1152/japplphysiol.00924.2001 | quote = Consolidation of sleep for 8 h or more is only observed when sleep is initiated ~6–8 h before the temperature nadir. | s2cid = 2502686 }}</ref> Along with corresponding messages from the circadian clock, this tells the body it needs to sleep.<ref name="autogenerated1">{{cite web|url=https://www.helpguide.org/life/sleeping.htm |title=Understanding Sleep: Sleep Needs, Cycles, and Stages |access-date=25 January 2008 | vauthors = de Benedictis T, Larson H, Kemp G, Barston S, Segal R |year=2007 |publisher=Helpguide.org |url-status=dead |archive-url=https://web.archive.org/web/20080124000744/https://www.helpguide.org/life/sleeping.htm |archive-date=24 January 2008 }}</ref> The timing is correct when the following two circadian markers occur after the middle of the sleep episode and before awakening:<ref name=Wyatt1999 /> maximum concentration of the hormone melatonin, and minimum core body temperature.