Polyphasic sleep

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Polyphasic sleep, a term coined by early 20th century psychologist J.S. Szymanski,[1] 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 an 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.[2]

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.

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[edit] 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.[3] 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. It purportedly shows that all stages of sleep were included.[4] 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)."[5]

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."[6]

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.[7]

[edit] 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 notes:

"Eventually he had to quit because his schedule conflicted with that of his business associates, who insisted on sleeping like other men."[8]

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. The systematic napping patterns are, by the online proponents, called variously polynapping, polyphasic sleep, Everyman sleep schedule and Uberman's sleep schedule. People who have tried and given up living on just ultrashort naps often give social reasons, similar to Fuller's above.

The anecdotal information about napping to reduce total sleep time comes from claims on blogs. A field study conducted by Dr. Claudio Stampi, published in 1989 in the peer-reviewed journal Work & Stress, concluded that "polyphasic sleep strategies improve prolonged sustained performance" under continuous work situations.[9]

Some[citation needed] believe that after undergoing controlled sleep deprivation during an initial adjustment period, the brain will start to enter the most 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 only in naps can be established.

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), and express concern that the ways in which the ultrashort nappers 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 them 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.[10] The online journals of those who have difficulty waking at specific intervals without oversleeping, offer anecdotal evidence that the pattern is unsustainable according to critics.

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.[11]

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!"[12]

[edit] References

  1. ^ Danchin, Antoine. "Important dates 1900-1919". HKU-Pasteur Research Centre. 
  2. ^ Mori, A. (January 1990). "Sleep disturbance in the elderly" (Abstract). Nippon Ronen Igakkai Zasshi 27 (1). PMID 2191161. 
  3. ^ Wanjek, Christopher (2007-12-18). "Can You Cheat Sleep? Only in Your Dreams". LiveScience. 
  4. ^ Alda, Alan (Show 105) (1991-02-27). Catching catnaps (transcript). PBS. Retrieved on 2008-02-19. “video”
  5. ^ Caldwell, John A., Ph.D. (February 2003). "An Overview of the Utility of Stimulants as a Fatigue Countermeasure for Aviators" (PDF, 24 pages). Brooks AFB, Texas: United States Air Force Research Laboratory. “(from Summary, page 19)” 
  6. ^ 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". Transport Canada, Transportation Development Centre. 
  7. ^ NASA-supported sleep researchers are learning new and surprising things about naps. NASA (03 June 2005). Retrieved on 2008-02-19.
  8. ^ "Dymaxion Sleep" (1943-10-11). Time Magazine. 
  9. ^ Stampi, Dr. Claudio (January 1989). Polyphasic sleep strategies improve prolonged sustained performance: A field study on 99 sailors. Work & Stress. Retrieved on 2008-06-02.
  10. ^ Wozniak, Dr. Piotr (January 2005). "Polyphasic Sleep: Facts and Myths". Super Memory (website). “This article compares polyphasic sleep to regular monophasic sleep, biphasic sleep, as well as to the concept of free-running sleep” 
  11. ^ Breus, Dr. Michael (19 April 2006). Sleep Hacker Backs Off. WebMD. Retrieved on 2008-02-19.
  12. ^ Mednick, Sara (11 May 2007). Uberman, napping is all there is.... Retrieved on 2008-03-23.

[edit] External links