Power nap
{{short description|Short sleep}}
File:Nappuccino café napping pods Barcelona.jpg, in the café Nappuccino in Barcelona, Catalonia (Spain)]]
A power nap or cat nap is a short sleep that terminates before deep sleep (slow-wave sleep; SWS). A power nap is intended to quickly revitalize the sleeper.
A power nap combined with consuming caffeine is called a stimulant nap, coffee nap, caffeine nap, or nappuccino.
Characteristics
A power nap, also known as a Stage 2 nap, is a short slumber of 20 minutes or less which terminates before the occurrence of deep slow-wave sleep, intended to quickly revitalize the napper. The expression "power nap" was coined by Cornell University social psychologist James Maas.{{cite book |last=Mednick |first=Sara C. |author2=Mark Ehrman |title=Take a Nap! Change Your Life |year=2006 |edition=First |publisher=Workman Publishing |location=New York, NY, USA |isbn=978-0-7611-4290-4 |url-access=registration |url=https://archive.org/details/takenapchangeyou00medn }}
The 20-minute nap increases alertness and motor skills. Various durations may be recommended for power naps, which are short compared to regular sleep. The short duration prevents nappers from sleeping so long that they enter the slow wave portion of the normal sleep cycle without being able to complete the cycle. Entering deep, slow-wave sleep and failing to complete the normal sleep cycle, can result in a phenomenon known as sleep inertia, where one feels groggy, disoriented, and even sleepier than before beginning the nap. In order to attain optimal post-nap performance, a Stage 2 nap must be limited to the beginning of a sleep cycle, specifically sleep stages N1 and N2, typically 18–25 minutes.
Experimental confirmation of the benefits of this brief nap comes from a Flinders University study in Australia in which 5, 10, 20, or 30-minute periods of sleep were given. The greatest immediate improvement in measures of alertness and cognitive performance came after the 10 minutes of sleep. The 20 and 30-minute periods of sleep showed evidence of sleep inertia immediately after the naps and improvements in alertness more than 30 minutes later, but not to a greater level than after the 10 minutes of sleep.{{cite journal |last=Brooks |first=A |author2=Lack, L. |year=2006 |url=https://www.scopus.com/record/display.url?eid=2-s2.0-33745118693&origin=inward&txGid=350283ECD84BD6A56AA7FBA2A5F7C097.53bsOu7mi7A1NSY7fPJf1g%3a1 |title=A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative? |journal=Sleep |volume=29 |issue=6 |pages=831–840 |access-date=18 April 2015|doi=10.1093/sleep/29.6.831 |pmid=16796222 |doi-access=free }} Power naps are effective even when schedules allow a full night's sleep.{{cite journal |title=The effects of a 20-min nap before post-lunch dip |journal=Psychiatry and Clinical Neurosciences |volume=52 |issue=2 |pages=203–204 |date=1 April 1998 |doi=10.1111/j.1440-1819.1998.tb01031.x |pmid=9628152 |last1=Hayashi |first1=Mitsuo |last2=Hori |first2=Tadao |s2cid=14147227 }}
Research
=Potential benefits=
Power naps intend to restore alertness, performance, and learning ability.{{Cite journal |last1=Dhand |first1=Rajiv |last2=Sohal |first2=Harjyot |year=2007 |title=Good sleep, bad sleep! The role of daytime naps in healthy adults |journal=Current Opinion in Internal Medicine |volume=6 |issue=6 |pages=91–94 |doi=10.1097/01.mcp.0000245703.92311.d0 |pmid=17053484|s2cid=30067543 }}{{cite journal |doi=10.1111/j.1365-2869.2008.00622.x |title=An ultra short episode of sleep is sufficient to promote declarative memory performance |year=2008 |last1=Lahl |first1=Olaf |last2=Wispel |first2=Christiane |last3=Willigens |first3=Bernadette |last4=Pietrowsky |first4=Reinhard |journal=Journal of Sleep Research |volume=17 |pages=3–10 |pmid=18275549 |issue=1|s2cid=12623878 |doi-access=free }} A nap may also reverse the hormonal impact of a night of poor sleep or reverse the damage of sleep deprivation.{{cite web|url=http://www.sciencealert.com/napping-may-be-able-to-reverse-the-damage-of-sleep-deprivation|title=Napping may be able to reverse the damage of sleep deprivation|publisher=sciencealert|access-date=10 February 2015}} A University of Düsseldorf study found superior memory recall once a person had reached 6 minutes of sleep, suggesting that the onset of sleep may initiate active memory processes of consolidation which—once triggered—remains effective even if sleep is terminated.
According to clinical studies among men and women, power nappers of any frequency or duration had a significantly lower mortality ratio due to heart disease than those not napping. Specifically, those occasionally napping had a 12% lower coronary mortality, whereas those systematically napping had a 37% lower coronary mortality.{{Cite journal|last=Naska|first=Androniki|date=2007-02-12|title=Siesta in Healthy Adults and Coronary Mortality in the General Population|journal=Archives of Internal Medicine|language=en|volume=167|issue=3|pages=296–301|doi=10.1001/archinte.167.3.296|pmid=17296887|issn=0003-9926|doi-access=free}}
A Flinders University study of individuals restricted to only five hours of sleep per night found a 10-minute nap was overall the most recuperative nap duration of various nap lengths they examined (lengths of 0 min, 5 min, 10 min, 20 min, and 30 minutes): the 5-minute nap produced few benefits in comparison with the no-nap control; the 10-minute nap produced immediate improvements in all outcome measures (including sleep onset latency, subjective sleepiness, fatigue, vigor, and cognitive performance), with some of these benefits maintained for as long as 155 minutes; the 20-minute nap was associated with improvements emerging 35 minutes after napping and lasting up to 125 minutes after napping; and the 30-minute nap produced a period of impaired alertness and performance immediately after napping, indicative of sleep inertia, followed by improvements lasting up to 155 minutes after the nap.{{cite journal |pmid=16796222 |year=2006 |last1=Brooks |first1=A |last2=Lack |first2=L |title=A brief afternoon nap following nocturnal sleep restriction: Which nap duration is most recuperative? |volume=29 |issue=6 |pages=831–40 |journal=Sleep|doi=10.1093/sleep/29.6.831 |doi-access=free }}
The NASA Ames Fatigue Countermeasures Group studied the effects of sleep loss and jet lag, and conducts training to counter these effects. A major fatigue countermeasures recommendation consists of a 40-minute nap ("NASA nap") which empirically showed to improve flight crew performance and alertness with a 22% statistical risk of entering SWS.{{cite web |url=http://human-factors.arc.nasa.gov/zteam/fcp/pubs/jsr.art.html |title=NASA: Alertness Management: Strategic Naps in Operational Settings |year=1995 |access-date=2012-04-16 |url-status=dead |archive-url=https://web.archive.org/web/20120419073208/http://human-factors.arc.nasa.gov/zteam/fcp/pubs/jsr.art.html |archive-date=2012-04-19 }}
For several years, scientists have been investigating the benefits of napping, both the power nap and much longer sleep durations as long as 1–2 hours. Performance across a wide range of cognitive processes has been tested. Studies demonstrate that naps are as good as a night of sleep for some types of memory tasks.
A NASA study led by David F. Dinges, professor at the University of Pennsylvania School of Medicine, found that naps can improve certain memory functions.{{cite journal |doi=10.1016/j.actaastro.2006.09.022 |title=Optimizing sleep/wake schedules in space: Sleep during chronic nocturnal sleep restriction with and without diurnal naps |year=2007 |last1=Mollicone |first1=Daniel J. |last2=Van Dongen |first2=Hans P.A. |last3=Dinges |first3=David F. |journal=Acta Astronautica |volume=60 |issue=4–7 |pages=354|bibcode=2007AcAau..60..354M }} In that NASA study, volunteers spent several days living on one of 18 different sleep schedules, all in a laboratory setting. To measure the effectiveness of the naps, tests probing memory, alertness, response time, and other cognitive skills were used.
Power Napping Enablers and sleep timers allow properly timed power napping.
One study showed that a midday snooze reverses information overload. Reporting in Nature Neuroscience, Sara Mednick, PhD, Stickgold and colleagues also demonstrated that "burnout" irritation, frustration and poorer performance on a mental task can set in as a day of training wears on. This study also proved that, in some cases, napping could even boost performance to an individual's top levels. The NIMH team wrote: "The bottom line is: we should stop feeling guilty about taking that 'power nap' at work."{{cite web |url=http://www.nih.gov/news/pr/jul2002/nimh-02.htm |title=The National Institute of Mental Health Power Nap Study |date=2002-07-01 |access-date=2002-07-01 |url-status=dead |archive-url=https://web.archive.org/web/20020802060144/http://www.nih.gov/news/pr/jul2002/nimh-02.htm |archive-date=2002-08-02 }}
The Centers for Disease Control and Prevention studied the effects of socioeconomic status on short sleep durations. In this 2007-2008 CDCP study, 4,850 National Health and Nutrition Examination Survey (NHANES) produced self-reported sleep durations. It was suggested through this study that individuals with minority status and a lower ranking in socioeconomic position are more inclined to have shorter self-reported sleep [https://www.sciencedirect.com/science/article/abs/pii/S1389945710000961 durations].{{Cite journal |last=Grandner |first=Michael A. |last2=Patel |first2=Nirav P. |last3=Gehrman |first3=Philip R. |last4=Xie |first4=Dawei |last5=Sha |first5=Daohang |last6=Weaver |first6=Terri |last7=Gooneratne |first7=Nalaka |date=2010-05-01 |title=Who gets the best sleep? Ethnic and socioeconomic factors related to sleep complaints |url=https://www.sciencedirect.com/science/article/abs/pii/S1389945710000961 |journal=Sleep Medicine |volume=11 |issue=5 |pages=470–478 |doi=10.1016/j.sleep.2009.10.006 |issn=1389-9457|pmc=2861987 }}
=Potential risks and detriments=
{{Expand section|date=April 2022}}
Longer and more frequent daytime naps appeared to be associated with a higher risk of Alzheimer's dementia in a study that tracked 1401 older people over 14 years.{{cite news |title=Long naps may be early sign of Alzheimer's disease, study shows |url=https://www.theguardian.com/society/2022/mar/17/naps-early-sign-alzheimers-disease-study |access-date=18 April 2022 |work=The Guardian |date=17 March 2022 |language=en}}{{cite journal |last1=Li |first1=Peng |last2=Gao |first2=Lei |last3=Yu |first3=Lei |last4=Zheng |first4=Xi |last5=Ulsa |first5=Ma Cherrysse |last6=Yang |first6=Hui-Wen |last7=Gaba |first7=Arlen |last8=Yaffe |first8=Kristine |last9=Bennett |first9=David A. |last10=Buchman |first10=Aron S. |last11=Hu |first11=Kun |last12=Leng |first12=Yue |title=Daytime napping and Alzheimer's dementia: A potential bidirectional relationship |journal=Alzheimer's & Dementia |date=17 March 2022 |volume=19 |issue=1 |pages=158–168 |doi=10.1002/alz.12636 | pmid=35297533 |pmc=9481741 |language=en |issn=1552-5260 }} Links have also been proposed between these types of naps and cardiovascular disease, though the evidence is largely inconclusive. A series of studies by the medical journal Sleep demonstrated that people who nap for an hour or more a day had 1.82 times the rate of cardiovascular disease than people who didn't nap.{{Cite web |last=Precker |first=Michael |date=July 22, 2020 |title=Enjoy your nap, but be aware of the pros and cons |url=https://www.heart.org/en/news/2020/07/22/enjoy-your-nap-but-be-aware-of-the-pros-and-cons |website=American Heart Association}}{{Cite journal |last1=Yamada |first1=Tomohide |last2=Hara |first2=Kazuo |last3=Shojima |first3=Nobuhiro |last4=Yamauchi |first4=Toshimasa |last5=Kadowaki |first5=Takashi |date=December 1, 2015 |title=Daytime Napping and the Risk of Cardiovascular Disease and All-Cause Mortality: A Prospective Study and Dose-Response Meta-Analysis |journal=Sleep |volume=38 |issue=12 |pages=1945–1953 |doi=10.5665/sleep.5246 |pmid=26158892 |pmc=4667384 }}
{{anchor|Coffee nap}}Stimulant nap
A stimulant nap is a brief period of sleep of around 15 minutes, preceded by consuming a caffeinated drink or another stimulant.
It may combat daytime drowsiness more effectively than napping or drinking coffee alone. A stimulant nap is more effective than regular naps in improving post-nap alertness and cognitive functioning. In a driving simulator and a series of studies, Horne and Reyner investigated the effects of cold air, radio, a break with no nap, a nap, caffeine pill vs. placebo and a short nap preceded by caffeine on mildly sleep-deprived subjects. A nap with caffeine was by far the most effective in reducing driving accidents and subjective sleepiness as it helps the body get rid of the sleep-inducing chemical compound adenosine.{{unreliable source?|date=February 2021}} Caffeine in coffee takes up to half an hour to have an alerting effect, hence "a short (<15min) nap will not be compromised if it is taken immediately after the coffee."{{cite journal |pmid=9485532 |year=1998 |last1=Reyner |first1=LA |last2=Horne |first2=JA |title=Evaluation 'in-car' countermeasures to sleepiness: Cold air and radio |volume=21 |issue=1 |pages=46–50 |journal=Sleep}}{{cite journal |doi=10.1111/j.1365-2869.1995.tb00222.x |title=Driver sleepiness |year=1995 |last1=Horne |first1=J. A. |last2=Reyner |first2=L. A. |journal=Journal of Sleep Research |volume=4 |pmid=10607207 |pages=23–29 |issue=S2|s2cid=45193968 |doi-access=free }}{{cite web |title= Loughborough University researchers issue new warning to tired drivers |url=http://www.lboro.ac.uk/service/publicity/news-releases/2004/04_110_micro-sleep.html |access-date=2007-09-23}} One account suggested that it was like a "double shot of energy" from the stimulating boost from caffeine plus better alertness from napping. This procedure has been studied on sleep-deprived humans given the task of driving a motor vehicle afterwards, although it has not been studied on elderly populations.
Nap rooms and tech aided naps
File:EnergyPod at Wesleyan University.jpg, located in a small nap room of the Olin library at Wesleyan University{{cite news|last1=Schwartz|first1=Meredith|title=Napping in the Library—On Purpose|url=http://lj.libraryjournal.com/2012/10/library-services/napping-in-the-library-on-purpose/|access-date=24 February 2015|work=Library Journal|date=24 October 2012}}]]
Some companies have nap rooms to allow employees to take power naps. This may be in a form of a nap room with a recliner, or chairs specially designed for power napping installed in a designated area. Companies with nap rooms say that employees are happier and become more productive at work.{{cite news|last1=Stump|first1=Scott|title='Nap rooms' encourage sleeping on the job to boost productivity|url=http://www.today.com/money/nap-rooms-encourage-sleeping-job-boost-productivity-1C8881304|access-date=23 February 2015|work=TODAY Money|date=15 March 2013}}
Similar nap rooms and stations also exist in higher education institutions. Many colleges and universities provide napping furnitures such as cots and beanbags in libraries for students to take naps after long periods of study. At least one university{{which|date=October 2017}} has a nap room set up in a gym. Some medical schools also set up nap rooms at teaching hospitals. The nap rooms may include sleeping pods or cots, white noise machines, and antimicrobial pillows.{{cite magazine|last1=Waxman|first1=Olivia B.|title=Napping Around: Colleges Provide Campus Snooze Rooms|url=https://time.com/3211964/nap-rooms-at-universities/|access-date=23 February 2015|magazine=TIME|date=29 August 2014}}
In Barcelona, there is a café called NappuccinoRomero, Shantal (18 June 2019) [https://www.rsvponline.mx/must/nappuccino-conoce-el-primer-cafe-en-el-mundo-en-donde-puedes-dormir "Nappuccino: Conoce el primer café en el mundo en donde puedes dormir". RSVP](16 March 2019)[https://www.france.tv/france-2/telematin/926927-telematin.html "Télématin France 2 TV". FRANCE 2 TV 2h27min] that implements custom-built napping pods inside the café.
A more portable aid is a nap timer app. Apps have various features including aided sounds, nap history and pattern tracking and daily reminders that make it easier to take naps.
See also
- {{annotated link|Nap}}
- {{annotated link|Siesta}}
- {{annotated link|Sleeping while on duty}}
References
{{Reflist
|refs =
Rose Eveleth, Smithsonian magazine, OCTOBER 24, 2013, [http://www.smithsonian.com/smart-news/what-is-the-exactly-perfect-time-to-drink-your-coffee-4836104/ What Is the Exactly Perfect Time to Drink Your Coffee? It's a good thing that science is here to figure out the exact perfect way to drink a cup of coffee], Retrieved Aug. 29, 2014, "...taking a 15 minute (no longer) nap right after you chug your coffee..."
An Unashamed Defense of Coffee, Authors: Roseane M. Santos, Roseane M. Santos, M.Sc., Ph.D. & Darcy R. Lima, M.D., Ph.D., Darcy R. Lima, Xlibris Corporation publishers, 2009, [https://books.google.com/books?id=04SIv_mh-C4C&dq=%28%22coffee+nap%22+OR+%22caffeine+nap%22%29&pg=PA66 ], Retrieved Aug. 29, 2014, (see page 66), "...researchers found worked best was a Caffeine Nap..."{{Self-published inline|certain=yes|date=December 2017}}
}}
Further reading
- Maas, James. Power Sleep : The Revolutionary Program That Prepares Your Mind for Peak Performance; William Morrow Paperbacks; 1st edition, 19 December 1998; {{ISBN|978-0060977603}}.
External links
- [http://archive.boston.com/bostonglobe/ideas/naps/ Boston Globe article on power naps]
- [https://www.youtube.com/watch?v=vsgJgOT-pl4 University of Miami : "Sleep, Napping and the Brain -The Power of Napping"], YouTube
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