Sleep efficiency (SE) is the ratio between the time a person spends asleep, and the total time dedicated to sleep (i.e. both sleeping and attempting to fall asleep or fall back asleep). It is given as a percentage.[1] SE of 80% or more is considered normal/healthy with most young healthy adults displaying SE above 90%.[2][better source needed] SE can be determined with a polysomnograph and is an important parameter of a sleep study.[3]

Sleep efficiency is often described as the ratio between time spent asleep ("total sleep time (TST)"), and time spent "in bed" ("time in bed (TIB)"), however, TIB does not encompass "non-sleep-related activities" performed in bed (e.g. reading, watching television, etc.) as the phrase may seem to suggest.[1]

Clinical significance

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Long sleep duration may be a sign of low sleep efficiency.[4] SE is significantly reduced in insomnia; SE is therefore an important clinical parameter in clinical investigations of insomnia.[1] SE declines with age and low SE is common in the elderly.[5] Furthermore, lower values of SE are often observed in sleep studies on pregnant populations and are mostly explained by the increased awakening periods after sleep onset (''wake after sleep onset (WASO)'').[6]

References

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  1. ^ a b c Reed, David L.; Sacco, William P. (2016-02-15). "Measuring Sleep Efficiency: What Should the Denominator Be?". Journal of Clinical Sleep Medicine. 12 (2): 263–266. doi:10.5664/jcsm.5498. ISSN 1550-9389. PMC 4751425. PMID 26194727.
  2. ^ "Interpreting A Sleep Study". Sleep WA. Retrieved 2021-05-17.
  3. ^ Shrivastava, Deepak; Jung, Syung; Saadat, Mohsen; Sirohi, Roopa; Crewson, Keri (2014-11-25). "How to interpret the results of a sleep study". Journal of Community Hospital Internal Medicine Perspectives. 4 (5): 24983. doi:10.3402/jchimp.v4.24983. ISSN 2000-9666. PMC 4246141. PMID 25432643.
  4. ^ Chaput, Jean-Philippe; Dutil, Caroline; Sampasa-Kanyinga, Hugues (2018-11-27). "Sleeping hours: what is the ideal number and how does age impact this?". Nature and Science of Sleep. 10: 421–430. doi:10.2147/NSS.S163071. ISSN 1179-1608. PMC 6267703. PMID 30568521.
  5. ^ Desjardins, Sophie; Lapierre, Sylvie; Hudon, Carol; Desgagné, Alain (2019-02-15). "Factors involved in sleep efficiency: a population-based study of community-dwelling elderly persons". Sleep. 42 (5). doi:10.1093/sleep/zsz038. ISSN 0161-8105. PMC 6519908. PMID 30768200.
  6. ^ Wilson, Danielle L.; Barnes, Maree; Ellett, Lenore; Permezel, Michael; Jackson, Martin; Crowe, Simon F. (February 2011). "Decreased sleep efficiency, increased wake after sleep onset and increased cortical arousals in late pregnancy: Decreased sleep efficiency in late pregnancy". Australian and New Zealand Journal of Obstetrics and Gynaecology. 51 (1): 38–46. doi:10.1111/j.1479-828X.2010.01252.x. PMID 21299507. S2CID 1125445.