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Polyphasic sleep, a term coined by early 20th century psychologist J.S. Szymanski, refers to the practice of sleeping multiple times in a 24-hour period -- usually, more than two, in contrast to "biphasic sleep" -- and does not imply any particular schedule. See also Segmented sleep and Sleep (Optimal amount). The term polyphasic sleep is also used by the online community which experiments with ultra-short napping to achieve more wake-time each day.
An example of polyphasic sleep is found in patients with irregular sleep-wake pattern, a circadian rhythm sleep disorder which usually is caused by head injury or dementia. Much more common examples are the sleep of human infants and of many animals. Elderly humans often have disturbed sleep, including polyphasic sleep.
The adult human body clock adjusts well to monophasic sleep in accordance with the individual's chronotype. Biphasic sleep with a long sleep episode at night and a "siesta" in early afternoon is also easily explained and justified by circadian rhythm research.
Napping in extreme situations
In crisis and other extreme conditions, people may not be able to achieve the recommended eight hours of sleep per day. Systematic napping may be considered necessary in such situations.
Dr. Claudio Stampi, as a result of his interest in long-distance solo boat racing, has studied the systematic timing of short naps as a means of ensuring optimal performance in situations where extreme sleep deprivation is inevitable, but he does not advocate ultrashort napping as a lifestyle. Scientific American Frontiers (PBS) has reported on Stampi's 49-day experiment where a young man napped for a total of three hours per day. Stampi has written about his research in his book "Why We Nap: Evolution, Chronobiology, and Functions of Polyphasic and Ultrashort Sleep" (1992).
The US military has studied fatigue countermeasures. An Air Force report states:
- "Each individual nap should be long enough to provide at least 45 continuous minutes of sleep, although longer naps (2 hours) are better. In general, the shorter each individual nap is, the more frequent the naps should be (the objective remains to acquire a daily total of 8 hours of sleep)."
Similarly, the Canadian Marine Pilots in their trainer's handbook report that:
- "[u]nder extreme circumstances where sleep cannot be achieved continuously, research on napping shows that 10- to 20-minute naps at regular intervals during the day can help relieve some of the sleep deprivation and thus maintain minimum levels of performance for several days. However, researchers caution that levels of performance achieved using ultrashort sleep (short naps) to temporarily replace normal sleep, are always well below that achieved when fully rested."
NASA, in cooperation with the National Space Biomedical Research Institute, has funded research on napping. Despite NASA recommendations that astronauts sleep 8 hours a day when in space, they usually have trouble sleeping 8 hours at a stretch, so the agency needs to know about the optimal length, timing and effect of naps. Professor David Dinges of the University of Pennsylvania School of Medicine led research in a laboratory setting on sleep schedules which combined various amounts of "anchor sleep," ranging from about 4 to 8 hours in length, with daily naps of 0 to 2.5 hours. Longer naps were found to be better, with some cognitive functions benefiting more from napping than others. Vigilance and basic alertness benefited the least while working memory benefited greatly. Naps in the individual subjects' biological daytime worked well, but naps in their nighttime were followed by much greater sleep inertia lasting up to an hour.
Scheduled napping to achieve more wake time
In an early mention of systematic napping as a lifestyle, Buckminster Fuller advocated his "Dymaxion Sleep," a regimen consisting of 30 minute naps every six hours, which he said he'd followed for two years. The short article about Fuller's sleep in TIME in 1943 also refers to such a schedule as "intermittent sleeping", and it states:
- "Eventually he had to quit because his schedule conflicted with that of his business associates, who insisted on sleeping like other men."
Within the last decade, several bloggers have experimented with alternative sleep patterns intended to reduce sleep time to 2–6 hours daily in order to get more wake time. This is purportedly achieved by spreading out sleep into short naps of around 15–45 minutes throughout the day, and in some variants, a core sleep period of a few hours at night. People who have tried and given up living on just ultrashort naps often give social reasons, similar to Fuller's above.
The systematic napping patterns are, by the online proponents, called variously polyphasic sleep, Everyman sleep schedule and Uberman's sleep schedule. The latter consists of six naps of 20–25 minutes each, occurring four hours apart throughout the day. This is the closest schedule to the type that has been studied by Claudio Stampi in connection with long-distance solo boat races. The names Uberman and Everyman were coined by the same blogger, calling herself "PureDoxyK", very early in the 21st century.
The process of adapting to a schedule of a few short naps can involve a mentally and physically very difficult 30 day adaptation period. Bloggers' experiences and scientific evidence from Claudio Stampi both suggest that most tiredness dissipates around 10 days into the schedule, and it disappears completely after about 14 days.[How to reference and link to summary or text]
Different sleep patterns may give individually varied results; the blogger Steve Pavlina reported difficulty switching from Uberman's sleep schedule to Fuller's Dymaxion sleep schedule and gave up the attempt. WebMD's Dr. Breus ended his short series on Sleep Hackers by reporting Pavlina's return to monophasic sleep in 2006.
Most intentional polyphasic sleepers tend to claim that the most difficult aspect of the sleep pattern to overcome is the social aspect, as the work hours of modern careers generally do not allow for the required nap periods at regular intervals. Personal accounts indicate that missing even one nap can cause heavy drowsiness, and thus even successful polyphasic sleepers often revert to monophasic sleep to accommodate their schedules.
Normal sleep consists of several stages (I, II, III, IV and REM). Some people[How to reference and link to summary or text] believe that after undergoing controlled sleep deprivation during an initial adjustment period, the brain will start to enter the essential sleep stages much more quickly, as a survival strategy. Once this adaptation is learned, the theory goes, a comfortable and sustainable equilibrium of sleeping in only naps can be established.
Much, if not most, of the anecdotal information about napping with the intention of reducing total sleep time per day, comes from the claims of independent testers; it has not been considered by mainstream science.
REM and non-REM sleep are equally important for healthy sleep. Depressed people are known to experience more REM sleep and monoamine oxidase inhibitors nearly completely abolish REM sleep, yet patients who take MAOIs do not exhibit any obvious cognitive deficits.
Critics consider the theory behind severe reduction of total sleep time by way of short naps unsound, claiming that there is no brain control mechanism that would make it possible to adapt to the "multiple naps" system. They say that the body will always tend to consolidate sleep into at least one solid block (usually during the night or early in the morning). They often point to the fact that there is no scientific evidence, specifically that no articles have been published in any peer-reviewed scientific journals supporting the possibility of entrainment to the polyphasic pattern.
Sara Mednick, Ph.D., whose sleep research investigates napping, included a chapter, Extreme Napping, in her book Take a Nap! Change Your Life. In response to questions from readers about the uberman schedule, she wrote in May 2007:
- "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!"
Even though Stampi's experiment has shown that all stages of sleep are included, critics have expressed concern that the ways in which the ultrashort naps attempt to limit total sleep time, restrict time spent in the various stages of the sleep cycle, and disrupt the circadian rhythm of the body, will eventually cause subjects to suffer the same negative effects as those with other forms of sleep deprivation and circadian rhythm sleep disorders, such as decreased mental and physical ability, increased stress and anxiety, and a weakened immune system. Restricting total sleep time may also lead to "microsleeps" ("dropping off" or inattention for a few seconds at a time)[How to reference and link to summary or text] which may be dangerous when driving or operating machinery. Critics point to online journals of those who have difficulty waking at specific intervals without oversleeping, as anecdotal evidence that the pattern is unsustainable.
Polyphasic sleep is thought to increase REM sleep, but it may also be likely to upregulate slow-wave sleep(SWS), causing a polyphasic sleeper to gain less REM sleep per day than with standard sleep patterns.
Attributed polyphasic sleepers
Several famous people are said to have engaged in more or less systematic napping.
- Leonardo da Vinci - unverified; all that is known about Leonardo's sleep was written after his death. It is claimed that he slept only 15 minutes at a time, every two hours. The term "Da Vinci sleep" is sometimes used as a synonym for polyphasic sleep.
- Lord Byron, poet and hedonist.
- Paul Erdős, the itinerant mathematician, slept two hours a day for several decades through a combination of napping and amphetamine use.
- Steve Fossett, while flying non-stop around the world used 5-minute powernaps in regular intervals around the clock.
- Buckminster Fuller claimed to have napped for a half-hour every six hours for two years of his life; see above.
- Vilna Gaon is said to have slept four 30-minute intervals in 24 hours for much of his adult life. He would take three naps throughout the night and one during the day. Introduction to the Gra on Orach Chayim.
- Ellen McArthur, while sailing around the world used 3–10-minute catnaps frequently around the clock.
- Sir Hubert Opperman and thousands of other practitioners of the form of long-distance endurance cycling known as randonneuring have successfully completed events that required them to propel themselves over 1,200 km in less than 90 hours, under rules that effectively proscribe sleeping more than a few hours at a time. Many in fact sleep less than 30 minutes at a time over the challenging routes, such as Paris-Brest-Paris.
- P. Diddy spoke about sleeping habits similar to polyphasic sleep patterns on the show "MTV Diary," claiming that he sleeps between two to four hours a day by taking small naps.[How to reference and link to summary or text]
Popular myth has incorrectly labeled some icons as "polyphasic sleepers":
- Benjamin Franklin — Franklin did not hold sleep in high esteem, believing as many high achievers do that napping is a sign of laziness. This is evidenced by his quote, "There will be sleeping enough in the grave." However, he also wrote, "Early to bed and early to rise makes a man healthy, wealthy, and wise," and in a satirical piece, he proposed awakening Parisians by firing cannons in the morning so as to avoid wasting candles late at night.
- Thomas Edison — Edison is also known to have held sleep in contempt, claiming to sleep less than it was actually observed by his co-workers. He would frequently take naps on the floor lasting several hours, and kept a napping cot in his office for this purpose. He often worked throughout the night, and would usually sleep through most of the next day. Edison's only known diary, kept between July 12, 1885 and July 21, 1885, describes him generally waking at 5:00am, then continuing to fall back asleep and wake up for several more hours.  This pattern is not consistent with polyphasic sleep cycles. His famous naps were most likely a result of his irregular sleeping patterns and late night hours, not a result of a prescribed polyphasic regimen.
- Thomas Jefferson — Jefferson was not a polyphasic sleeper. He recounted his health and habits in a letter to Dr. Vine Utley, dated March 21, 1819; this letter described a nightly sleep period lasting five to eight hours, generally with 30-60 minutes of reading beforehand, and waking with the sunrise.
- Napoleon — Though the demands of leadership of an emperor may well have resulted in sleepless nights, no documents have been found to uphold a strategic schedule of polyphasic sleep.
- Nikola Tesla — Rather than being polyphasic, Tesla used to work excitedly for extended periods of time seemingly without fatigue (even above 70 hours). However, he has also been reported to sleep through the entire day. This would be an anti-polyphasic routine, which may be useful for following certain trains of thought and analysis.
- Albert Einstein - Einstein enjoyed occasional super-bouts of 9 hour sleep and was generally a long sleeper.
Polyphasic sleep in fiction
- Polyphasic sleep was also popularized on Seinfeld, when the character Kramer attempted to adapt to "Da Vinci's sleep pattern" in The Friars Club episode.
- Some writers have depicted Batman as sleeping only two hours every twenty four hours; the exact schedule has not been shown. In other instances Batman is mentioned to have stayed awake for up to three days straight.
- The character Shellman (Skalman) in Bamse is a polyphasic sleeper; using a special alarm clock as a reminder when to sleep and when to eat.
- In Ursula K. Le Guin's story The Word for World is Forest is set on a planet where the monkey-like hominids that make up the native population practice polyphasic sleeping naturally, finding alternative methods of sleep strange. Later, one human character attempts, with some success, to imitate the native sleep patterns.
- In Farley Mowat's novel Never Cry Wolf the main character takes what he calls "wolf naps," though no schedule seems present.
- In The Game, Neil Strauss (Style) attempts to adopt a polyphasic sleep regimen.
- In Lost (TV series), the character Desmond Hume is forced into a polyphasic sleep pattern by the need to enter a computer code every 108 minutes.
- Danchin, Antoine. Important dates 1900-1919. HKU-Pasteur Research Centre.
- Mori, A. (January 1990). Sleep disturbance in the elderly. Nippon Ronen Igakkai Zasshi 27 (1).
- Wanjek, Christopher (2007-12-18). Can You Cheat Sleep? Only in Your Dreams. LiveScience.
- Alda, Alan (Show 105) Catching catnaps (transcript). PBS. URL accessed on 2008-02-02.
- Caldwell, John A., Ph.D. (February 2003). An Overview of the Utility of Stimulants as a Fatigue Countermeasure for Aviators.
- Rhodes, Wayne, Ph.D., C.P.E., Gil, Valérie, Ph.D. (last updated 2007-01-17). Fatigue Management Guide for Canadian Marine Pilots – A Trainer's Handbook.
- NASA-supported sleep researchers are learning new and surprising things about naps. NASA. URL accessed on 19 February 2008.
- (1943-10-11)Dymaxion Sleep. Time Magazine.
- Breus, Dr. Michael Sleep Hacker Backs Off. WebMD. URL accessed on 2008-02-19.
- Kiser, Barbara (2003-04-12). The dreamcatcher. NewScientist (2390).
- Siegel, Jerome. M. (2001). The REM Sleep-Memory Consolidation Hypothesis. Science 294: 1058-1063.
- Mednick, Sara Uberman, napping is all there is.... URL accessed on 2008-03-23.
- Alda, Alan Catching Catnaps. (Video report on Stampi’s experiment) PBS. URL accessed on 2008-02-19.
- Wozniak, Dr. Piotr (January 2005). Polyphasic Sleep: Facts and Myths.
- Benjamin Franklin, as Poor Richard. WikiQuote: Benjamin Franklin. retrieved on 2008-03-10.
- Seymour Stanton Block (2006). Benjamin Franklin: America's inventor. American History.
- Benjamin Franklin, writing anonymously (1784-04-26). Aux auteurs du Journal. Journal de Paris (117). revised English version retrieved on 2007-05-26.
- includeonly>Edison, Thomas. "Thomas A. Edison Diary" (Personal Diary), 1885.
- includeonly>Jefferson, Thomas. "Letter from Thomas Jefferson to Dr. Vine Utley" (Personal Letter), March 21, 1819.
- Seinfeld Script that uses the term "Da Vinci Sleep"
- Claudio Stampi. (1992) Why We Nap: Evolution, Chronobiology, and Functions of Polyphasic and Ultrashort Sleep. ISBN 0-8176-3462-2
- Miles to Go Before I Sleep at Outside.com, April 2005.
- What You Can Do About Sleep Deprivation: Lessons from Around-the-World SailorsArticle by Claudio Stampi, M.D., Ph.D., March 2006, at Healthology.com
- Take a Nap! Change Your Life (Workman, 2006).
- Polyphasic Sleep Google Group resource pages - definitions, how-to guides, experiences, mailing list access
- Poly-Phasers.com - Polyphasic Sleep Community. Contains articles, links, an active forum, sleep logs (aka blogs) and a video gallery.
- PolyphasicSleep.info - informational wiki on polyphasic sleep
- Polyphasic Sleep Wiki - Actively maintained open repository for polyphasic sleep information
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