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Biphasic and polyphasic sleep

biphasic and polyphasic sleeping, biphasic and polyphasic sleep schedule
Biphasic sleep or bimodal or bifurcated sleep is the practice of sleeping during two periods over 24 hours, while polyphasic sleep refers to sleeping multiple times - usually more than two1 Each of these is in contrast to monophasic sleep which is one period of sleep over 24 hours Segmented sleep and divided sleep may refer to polyphasic or biphasic sleep, but may also refer to interrupted sleep where the sleep has one or several shorter periods of wakefulness A common form of biphasic or polyphasic sleep includes a nap, which is a short period of sleep, typically taken between the hours of 9am and 9pm as an adjunct to the usual nocturnal sleep period

The term polyphasic sleep was first used in the early 20th century by psychologist J S Szymanski, who observed daily fluctuations in activity patterns Stampi 1992 It does not imply any particular sleep schedule The circadian rhythm disorder known as irregular sleep-wake syndrome is an example of polyphasic sleep in humans Polyphasic sleep is common in many animals, and is believed to be the ancestral sleep state for mammals, although simians are monophasic2

The term polyphasic sleep is also currently used by an online community that experiments with alternative sleeping schedules to achieve more time awake each day However, researchers such as Piotr Woźniak warn that such forms of sleep deprivation are not healthy3 While many claim that polyphasic sleep was widely used by some polymaths and prominent people such as Leonardo da Vinci, Napoleon, or Nikola Tesla, there are few reliable sources supporting that view4


  • 1 Multiphasic sleep of normal total duration
  • 2 In extreme situations
    • 21 US military
    • 22 Canadian Marine pilots
    • 23 NASA
    • 24 Italian Air Force
  • 3 Biphasic sleep
  • 4 Interrupted sleep
    • 41 Historical norm
  • 5 Scheduled napping to achieve more time awake
    • 51 Buckminster Fuller
    • 52 Criticism
  • 6 See also
  • 7 References
  • 8 Further reading
  • 9 External links

Multiphasic sleep of normal total durationedit

An example of polyphasic sleep is found in patients with irregular sleep-wake syndrome, a circadian rhythm sleep disorder which usually is caused by neurological retardation, head injury or dementia5 Much more common examples are the sleep of human infants and of many animals Elderly humans often have disturbed sleep, including polyphasic sleep6

In their 2006 paper "The Nature of Spontaneous Sleep Across Adulthood,"7 Campbell and Murphy studied sleep timing and quality in young, middle-aged, and older adults They found that, in freerunning conditions, the average duration of major nighttime sleep was significantly longer in young adults than in the other groups The paper states further:

Whether such patterns are simply a response to the relatively static experimental conditions, or whether they more accurately reflect the natural organization of the human sleep/wake system, compared with that which is exhibited in daily life, is open to debate However, the comparative literature strongly suggests that shorter, polyphasically-placed sleep is the rule, rather than the exception, across the entire animal kingdom Campbell and Tobler, 1984; Tobler, 1989 There is little reason to believe that the human sleep/wake system would evolve in a fundamentally different manner That people often do not exhibit such sleep organization in daily life merely suggests that humans have the capacity often with the aid of stimulants such as caffeine or increased physical activity to overcome the propensity for sleep when it is desirable, or is required, to do so

In extreme situationsedit

In crises 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 lifestyle8 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 included9 Stampi has written about his research in his book Why We Nap: Evolution, Chronobiology, and Functions of Polyphasic and Ultrashort Sleep 199210 In 1989 he published results of a field study in the journal Work & Stress, concluding that "polyphasic sleep strategies improve prolonged sustained performance" under continuous work situations11

US militaryedit

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 sleep12

Canadian Marine pilotsedit

Similarly, the Canadian Marine pilots in their trainer's handbook report that:

Under 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 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 rested13


NASA, in cooperation with the National Space Biomedical Research Institute, has funded research on napping Despite NASA recommendations that astronauts sleep eight hours a day when in space, they usually have trouble sleeping eight 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 four to eight hours in length, with no nap or daily naps of up to 25 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 hour14

Italian Air Forceedit

The Italian Air Force Aeronautica Militare Italiana also conducted experiments for their pilots In schedules involving night shifts and fragmentation of duty periods through the entire day, a sort of polyphasic sleeping schedule was studied Subjects were to perform two hours of activity followed by four hours of rest sleep allowed, this was repeated four times throughout the 24-hour day Subjects adopted a schedule of sleeping only during the final three rest periods in linearly increasing duration The AMI published findings that "total sleep time was substantially reduced as compared to the usual 7–8 hour monophasic nocturnal sleep" while "maintaining good levels of vigilance as shown by the virtual absence of EEG microsleeps" EEG microsleeps are measurable and usually unnoticeable bursts of sleep in the brain while a subject appears to be awake Nocturnal sleepers who sleep poorly may be heavily bombarded with microsleeps during waking hours, limiting focus and attention15

Biphasic sleepedit

Further information: Siesta

An example of a biphasic sleep pattern is the practice of siesta, which is a nap taken in the early afternoon, often after the midday meal Such a period of sleep is a common tradition in some countries, particularly those where the weather is warm The siesta is historically common throughout the Mediterranean and Southern Europe It is the traditional daytime sleep of Spain and, through Spanish influence, the Philippines, and many Hispanic American countries Siesta is also common in Italy, where museums, churches and shops close during midday so that proprietors can go home for a long lunch and perhaps a snooze during the day’s hottest hours

One study suggests that during periods of short daylight ~10 hours, as in winter, humans will adopt a biphasic sleep pattern16 Another study indicates that this will happen whenever humans are removed from artificial light17

Interrupted sleepedit

Interrupted sleep is a primarily biphasic sleep pattern where two periods of nighttime sleep are punctuated by a period of wakefulness Along with a nap in the day, it has been argued that this is the natural pattern of human sleep in long winter nights1618 A case has been made that maintaining such a sleep pattern may be important in regulating stress18

Historical normedit

Historian A Roger Ekirch1719 has argued that before the Industrial Revolution, interrupted sleep was dominant in Western civilization He draws evidence from documents from the ancient, medieval, and modern world18 Other historians, such as Craig Koslofsky,20 have endorsed Ekirch's analysis

According to Ekirch's argument, adults typically slept in two distinct phases, bridged by an intervening period of wakefulness of approximately one hour19 This time was used to pray and reflect,21 and to interpret dreams, which were more vivid at that hour than upon waking in the morning This was also a favorite time for scholars and poets to write uninterrupted, whereas still others visited neighbors, engaged in sexual activity, or committed petty crime19:311–323

The human circadian rhythm regulates the human sleep-wake cycle of wakefulness during the day and sleep at night Ekirch suggests that it is due to the modern use of electric lighting that most modern humans do not practice interrupted sleep, which is a concern for some writers22 Superimposed on this basic rhythm is a secondary one of light sleep in the early afternoon

The brain exhibits high levels of the pituitary hormone prolactin during the period of nighttime wakefulness, which may contribute to the feeling of peace that many people associate with it23

The modern assumption that consolidated sleep with no awakenings is the normal and correct way for human adults to sleep, may lead people to consult their doctors fearing they have maintenance insomnia or other sleep disorders18 If Ekirch's hypothesis is correct, their concerns might best be addressed by reassurance that their sleep conforms to historically natural sleep patterns24

Ekirch has found that the two periods of night sleep were called "first sleep" occasionally "dead sleep" and "second sleep" or "morning sleep" in medieval England He found that first and second sleep were also the terms in the Romance languages, as well as in the language of the Tiv of Nigeria In French, the common term was premier sommeil or premier somme; in Italian, primo sonno; in Latin, primo somno or concubia nocte19:301–302 He found no common word in English for the period of wakefulness between, apart from paraphrases such as first waking or when one wakes from his first sleep and the generic watch in its old meaning of being awake In old French an equivalent generic term is dorveille, a portmanteau of the French words dormir to sleep and veiller to be awake

Because members of modern industrialised societies, with later evening hours facilitated by electric lighting, mostly do not practice interrupted sleep, Ekirch suggests that they may have misinterpreted and mistranslated references to it in literature Common modern interpretations of the term "first sleep" are "beauty sleep" and "early slumber" A reference to first sleep in the Odyssey was translated as "first sleep" in the seventeenth century, but, if Ekirch's hypothesis is correct, was universally mistranslated in the twentieth19:303

In his 1992 study, "In short photoperiods, human sleep is biphasic", Thomas Wehr had eight healthy men confined to a room for fourteen hours of darkness daily for a month At first the participants slept for about eleven hours, presumably making up for their sleep debt After this the subjects began to sleep much as people in pre-industrial times had They would sleep for about four hours, wake up for two to three hours, then go back to bed for another four hours They also took about two hours to fall asleep16

Scheduled napping to achieve more time awakeedit

Buckminster Fulleredit

In order to gain more time awake in the day, Buckminster Fuller reportedly advocated a regimen consisting of 30-minute naps every six hours The short article about Fuller's nap schedule in Time in 1943, which also refers to such a schedule as "intermittent sleeping," says that he maintained it for two years, and further notes "he had to quit because his schedule conflicted with that of his business associates, who insisted on sleeping like other men"25

However, it is not clear when Fuller practised any such sleep pattern and whether it was really as strictly periodic as claimed in that article; it has also been said that he ended this experiment because of his wife's objectionscitation needed


Critics such as Piotr Woźniak 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, and they 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 their circadian rhythms, 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 system26 Woźniak further claims to have scanned the blogs of polyphasic sleepers and found that they have to choose an "engaging activity" again and again just to stay awake and that polyphasic sleep does not improve one's learning ability or creativity

See alsoedit

  • REM rebound
  • Why We Nap book


  1. ^ Morin, Charles M; Espie, Colin A 2012 The Oxford Handbook of Sleep and Sleep Disorders Oxford University Press, USA p 224 ISBN 978-0-19-537620-3 
  2. ^ Capellini, I; Nunn, C L; McNamara, P; Preston, B T; Barton, R A 1 October 2008 "Energetic constraints, not predation, influence the evolution of sleep patterning in mammals" Functional Ecology 22 5: 847–853 doi:101111/j1365-2435200801449x PMC 2860325 PMID 20428321 
  3. ^ Woźniak, Piotr April 2010 "Polyphasic Sleep: 5 Years Later!" SuperMemo 
  4. ^ Woźniak, Piotr April 2010 "Polyphasic Sleep: Facts and Myths - Leonardo da Vinci" SuperMemo 
  5. ^ Zee, Phyllis C; Michael V Vitiello June 2009 "Circadian Rhythm Sleep Disorder: Irregular Sleep Wake Rhythm Type" Sleep Med Clin NIH Public Access 4 2: 213–218 doi:101016/jjsmc200901009 PMC 2768129 PMID 20160950 
  6. ^ Mori, A January 1990 "Sleep disturbance in the elderly" Nippon Ronen Igakkai Zasshi Abstract in English|format= requires |url= help Japan 27 1: 12–7 doi:103143/geriatrics2712 PMID 2191161 
  7. ^ Campbell, Scott S; Murphy, Patricia J March 2007 "The nature of spontaneous sleep across adulthood" Journal of Sleep Research 16 1: 24–32 doi:101111/j1365-2869200700567x PMID 17309760 
  8. ^ Wanjek, Christopher 18 December 2007 "Can You Cheat Sleep Only in Your Dreams" LiveScience 
  9. ^ Alda, Alan Show 105 1991-02-27 "Catching catnaps transcript" PBS Retrieved 2008-02-19 video 
  10. ^ Stampi, Claudio, ed 2013 Why We Nap: Evolution, Chronobiology, and Functions of Polyphasic and Ultrashort Sleep Springer Science & Business Media doi:101007/978-1-4757-2210-9 ISBN 978-1-4757-2210-9 page needed
  11. ^ Stampi, Claudio January 1989 "Polyphasic sleep strategies improve prolonged sustained performance: A field study on 99 sailors" Work & Stress: An International Journal of Work, Health & Organisations doi:101080/02678378908256879 
  12. ^ Caldwell, John A, PhD February 2003 "An Overview of the Utility of Stimulants as a Fatigue Countermeasure for Aviators" PDF Brooks AFB, Texas: United States Air Force Research Laboratory: 15 
  13. ^ Rhodes, Wayne, PhD, CPE; Gil, Valérie, PhD 17 January 2007 "Fatigue Management Guide for Canadian Marine Pilots – A Trainer's Handbook TP 13960E" Transport Canada, Transportation Development Centre Minimum Sleep Requirement 
  14. ^ "NASA-supported sleep researchers are learning new and surprising things about naps" NASA Science: Science News NASA 3 June 2005 
  15. ^ Porcu, S; Casagrande, M; Ferrara, M; Bellatreccia, A July 1998 "Sleep and Alertness During Alternating Monophasic and Polyphasic Rest-Activity Cycles" International Journal of Neuroscience 95 1–2: 43–50 doi:103109/00207459809000648 PMID 9845015 
  16. ^ a b c Wehr, TA June 1992 "In short photoperiods, human sleep is biphasic" Journal of Sleep Research 1 2: 103–107 doi:101111/j1365-28691992tb00019x PMID 10607034 
  17. ^ a b Ekirch, A Roger 2001 "Sleep We Have Lost: Pre-industrial Slumber in the British Isles" PDF American Historical Review Oxford University Press on behalf of the American Historical Association 106 2: 343–386 doi:102307/2651611 JSTOR 2651611 PMID 18680884 
  18. ^ a b c d Hegarty, Stephanie 22 February 2012 "The myth of the eight-hour sleep" BBC News 
  19. ^ a b c d e Ekirch, A Roger 2005 At Day's Close: Night in Times Past W W Norton ISBN 978-0-393-34458-5 page needed
  20. ^ Koslofsky, C M 2011 "An early modern revolution" Evening's Empire: A History of the Night in Early Modern Europe p 1 doi:101017/CBO9780511977695001 ISBN 9780511977695 
  21. ^ Frances Quarles London 1644, Enchirdion ch 54
  22. ^ Gamble, Jessa 2010 Our natural sleep cycle video TEDGlobal 2010, Oxford, England: TED Conferences, LLC Retrieved 2014-04-27 In today's world, balancing school, work, kids and more, most of us can only hope for the recommended eight hours of sleep Examining the science behind our body's internal clock, Jessa Gamble reveals the surprising and substantial program of rest we should be observing 
  23. ^ Randall, David K 2012 "2 Light My Fire" Dreamland: Adventures in the Strange Science of Sleep W W Norton pp 17–18 ISBN 978-0-393-08393-4 
  24. ^ Brown, Walter A, MD 26 May 2006 "Acknowledging Preindustrial Patterns of Sleep May Revolutionize Approach to Sleep Dysfunction" Psychiatric Times The discoveries of Ekirch and Wehr raise the possibility that interrupted sleep is "normal" and, as such, these revelations hold significant implications for both understanding sleep and the treatment of insomnia 
  25. ^ "Science: Dymaxion Sleep" Time Magazine 11 October 1943 Archived from the original on 2013-10-08 subscription required help 
  26. ^ Wozniak, Piotr January 2005 "Polyphasic Sleep: Facts and Myths" Super Memory Retrieved 2008-01-01 This article compares polyphasic sleep to regular monophasic sleep, biphasic sleep, as well as to the concept of free-running sleep 

Further readingedit

  • Everett, Daniel L 2008 Don't Sleep, there are Snakes, Pantheon Books ISBN 978-0-375-42502-8
  • Koslofsky, Craig 2011 Evening's Empire: A History of the Night in Early Modern Europe
  • Verdon, Jean, Night in the Middle Ages, trans George Holoch 2002 ISBN 0-268-03656-X
  • Warren, Jeff 2007 "The Watch" The Head Trip: Adventures on the Wheel of Consciousness Toronto: Random House Canada ISBN 978-0-679-31408-0 

External linksedit

  • Miles to Go Before I Sleep at Outsidecom, April 2005

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