{{Short description|Measurement of sleep duration}} '''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.<ref name=":0">{{Cite journal|last1=Reed|first1=David L.|last2=Sacco|first2=William P.|date=2016-02-15|title=Measuring Sleep Efficiency: What Should the Denominator Be?|journal=Journal of Clinical Sleep Medicine |volume=12|issue=2|pages=263–266|doi=10.5664/jcsm.5498|issn=1550-9389|pmc=4751425|pmid=26194727}}</ref> SE of 80% or more is considered normal/healthy with most young healthy adults displaying SE above 90%.<ref>{{Cite web|title=Interpreting A Sleep Study|url=https://www.sleepwa.com.au/interpreting-a-sleep-study/|access-date=2021-05-17|website=Sleep WA|language=en-US}}</ref>{{Better source needed|date=May 2021|reason=Presently, a non-scientific source is used.}} SE can be determined with a polysomnograph and is an important parameter of a sleep study.<ref>{{Cite journal|last1=Shrivastava|first1=Deepak|last2=Jung|first2=Syung|last3=Saadat|first3=Mohsen|last4=Sirohi|first4=Roopa|last5=Crewson|first5=Keri|date=2014-11-25|title=How to interpret the results of a sleep study|journal=Journal of Community Hospital Internal Medicine Perspectives|volume=4|issue=5|article-number=24983|doi=10.3402/jchimp.v4.24983|issn=2000-9666|pmc=4246141|pmid=25432643}}</ref>
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.<ref name=":0" />
Sleep efficiency plays a big role in insomnia research, since it shows the amount of time people are in bed for versus how much sleep they get. People with insomnia often spend lots of time in bed but get little sleep. This can often times increase stress and make the problem worse. Improving sleep efficiency is often a way to measure whether insomnia treatments are working. [https://pmc.ncbi.nlm.nih.gov/articles/PMC4751425/]
== Clinical significance == Long sleep duration may be a sign of low sleep efficiency.<ref>{{Cite journal|last1=Chaput|first1=Jean-Philippe|last2=Dutil|first2=Caroline|last3=Sampasa-Kanyinga|first3=Hugues|date=2018-11-27|title=Sleeping hours: what is the ideal number and how does age impact this?|journal=Nature and Science of Sleep|volume=10|pages=421–430|doi=10.2147/NSS.S163071|issn=1179-1608|pmc=6267703|pmid=30568521 |doi-access=free }}</ref> SE is significantly reduced in insomnia; SE is therefore an important clinical parameter in clinical investigations of insomnia.<ref name=":0" /> SE declines with age and low SE is common in the elderly.<ref>{{Cite journal|last1=Desjardins|first1=Sophie|last2=Lapierre|first2=Sylvie|last3=Hudon|first3=Carol|last4=Desgagné|first4=Alain|date=2019-02-15|title=Factors involved in sleep efficiency: a population-based study of community-dwelling elderly persons|journal=Sleep|volume=42|issue=5|doi=10.1093/sleep/zsz038|issn=0161-8105|pmc=6519908|pmid=30768200}}</ref> 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 (<nowiki>''wake after sleep onset (WASO)''</nowiki>).<ref>{{Cite journal |last1=Wilson |first1=Danielle L. |last2=Barnes |first2=Maree |last3=Ellett |first3=Lenore |last4=Permezel |first4=Michael |last5=Jackson |first5=Martin |last6=Crowe |first6=Simon F. |date=February 2011 |title=Decreased sleep efficiency, increased wake after sleep onset and increased cortical arousals in late pregnancy: Decreased sleep efficiency in late pregnancy |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1479-828X.2010.01252.x |journal=Australian and New Zealand Journal of Obstetrics and Gynaecology |language=en |volume=51 |issue=1 |pages=38–46 |doi=10.1111/j.1479-828X.2010.01252.x|pmid=21299507 |s2cid=1125445 |url-access=subscription }}</ref>
== References == {{Reflist}}
Category:Sleep medicine efficiency
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