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Hammock Napping on a Patio, In Costa Rica

A nap is a short period of sleep, usually in the day time. Naps may be taken when one becomes drowsy during the day, otherwise wants to feel awake later in the day, or as a traditional daily practice. It is common for small children to take frequent naps.


Effects of napping

Scientists have raised questions as to whether or not napping is beneficial[1]. Gregory Belenky, MD, Research Professor and Director of the Sleep and Performance Research Center at Washington State University, suggests that naps can make up for lost sleep during the night. However, prolonged naps, those exceeding 30 minutes, can lead to sleep inertia, causing the subject to be groggy after the nap.[1] Naps are not recommended for those suffering from insomnia or depression[2].

A contemporary fad called polyphasic sleep entails avoiding long sleeps, instead taking regularly spaced short naps. Sara Mednick, whose sleep research investigates the effects of napping, included a chapter, Extreme Napping, in her book Take a Nap!.[3] In response to questions from readers about the "uberman" schedule of "polyphasic sleeping", she commented as follows:

This practice rests upon one important hypothesis that our biological rhythms are adaptable. This means that we can train our internal mechanisms not only when to sleep and wake, but also when to get hungry, have energy for exercise, perform mental activities. Inferred in this hypothesis is that we have the power to regulate our mood, metabolism, core body temperature, endocrine and stress response, basically everything inside this container of flesh we call home. Truly an Uberman feat![4]

Research on the Benefits of Napping

Napping has been found to be beneficial. Napping for 20 minutes can help refresh the mind, improve overall alertness, boost mood and increase productivity.[5] Napping may benefit the heart. In a six-year study of Greek adults, researchers found that men who took naps at least three times a week had a 37 percent lower risk of heart-related death.[6]


A power-nap is a short sleep which terminates before the occurrence of deep sleep or slow-wave sleep (SWS), intended to quickly revitalize the person. The expression was coined by Cornell University social psychologist James Maas.[citation needed]



Power-napping is thought to maximize the benefits of sleep versus time. It is used to supplement normal sleep, especially when a person has accumulated a sleep deficit.

Various durations are recommended for a power-nap, which are very short compared to regular sleep. The short duration of a power-nap is intended to prevent 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 more sleepy than before beginning the nap. In order to attain optimal post-nap performance, it is critical that a power-nap be limited to the beginning of a sleep cycle, specifically sleep stages I and II (typically 18 to 25 minutes).

Scientific experiments (see Benefits section below) and anecdotal evidence suggest that an average power-nap duration of approximately 18 to 25 minutes is most effective. For any additional time, the mind enters into the deep sleep cycle. People who regularly take a power-nap may develop a good idea of what duration works best for them, as well as which tools, environment, position, and associated factors help induce the best results. Others may prefer to take a power-nap regularly even if their schedules allow a full night's sleep. Mitsuo Hayashi and Tadao Hori[7] have demonstrated that a nap improves mental performance, even after a full night's sleep.


Scientists have been investigating the benefits of napping for several years, especially the 20-minute power-nap, as well as sleep durations of 1–2 hours. Performance across a wide range of cognitive processes have 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.[8] 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.

The National Institute of Mental Health funded a team of doctors, led by Alan Hobson, Robert Stickgold, and colleagues at Harvard University for a study which showed that a midday snooze reverses information overload. Reporting in Nature Neuroscience, Sara Mednick, 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."[9]

The caffeine nap

A caffeine nap is a short nap that is preceded by the intake of caffeine. 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. The last mentioned was by far the most effective in reducing driving "incidents" and subjective sleepiness. Caffeine in coffee takes up to a half-hour to have an alerting effect, hence "a short (<15min) nap will not be compromised if it is taken immediately after the coffee."[10][11][12][13]

See also


  1. ^ a b
  2. ^
  3. ^ Mednick, Sara. Take a Nap! Change Your Life. Workman Publishing Co. 2006. ISBN 978-0761142904
  4. ^ Mednick, Sara (11 May 2007). "Uberman, napping is all there is...". -. Retrieved 2008-03-23. ; Archive link
  5. ^ Anthony, Camile and William. The Art of Napping at Work,Larson Publication, 1999.
  6. ^ [1], .
  7. ^ "The effects of a 20-min nap before post-lunch dip". 1998-04-01. Retrieved 2008-06-12. 
  8. ^ "NASA Nap". 2005-06-03. Retrieved 2007-08-24. 
  9. ^ "The National Institute of Mental Health Power-Nap Study". 2002-07-01. Retrieved 2002-07-01. 
  10. ^ Horne, JA; Reyner, LA (1996). "Driver sleepiness - "in-car" countermeasures: cold air and car radio" (Abstract). Sleep Research (25): 99. Retrieved 2009-02-09. 
  11. ^ Horne, JA; Reyner, LA (1995). "Driver sleepiness: practical countermeasures caffeine & nap" (Abstract). Sleep Research (24A): 438. Retrieved 2009-02-09. 
  12. ^ "Loughborough University researchers issue new warning to tired drivers". Retrieved 2007-09-23. 
  13. ^ Lifehacker article

External links

1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

NAP, the pile on cloth, the surface of short fibres raised by special processes, differing with the various fabrics, and then smoothed and cut. Formerly the word was applied to the roughness on textiles before shearing. "Nap" in this sense appears in many Teutonic languages, cf. Ger. Noppe, Dutch nop, Nor. napp; the verbal form is noppen or nappen, to trim, cut short. The word nap also means a short sleep or doze (0. Eng. hnappian). In "napkin," a square of damask or other linen, used for wiping the hands and lips or for protecting the clothes at meals, the second part is a common English suffix, sometimes of diminutive force, and the first is from "nape," 1 Low Lat. p apa or nappa, a corrupt form of mappa, table-cloth. Nape still survives in "napery," a name for household linen in general.

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Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

See also nap






  1. Sun
    A Nap a Naprendszer legnagyobb égiteste. - The Sun is the largest celestial body of the Solar System.



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