SherbyNet - /page/wikibook/entry.mu

Micron Document

<!DOCTYPE html>

<title>Polyphasic sleep</title>

</head>

Polyphasic sleep

</h1>

</header>

Polyphasic sleep or segmented sleep is the system of sleeping during multiple periods over the course of 24 hours, in contrast to monophasic sleep, a single period of sleep within 24 hours. Polyphasic usually means more than two periods of sleep, as distinct from biphasic (or diphasic, bifurcated, or bimodal) sleep, meaning two periods of sleep.<a href="#cite_note-Il99F-1">[1]</a> The term polyphasic sleep was first used in the early 20th century by psychologist J. S. Szymanski, who observed daily fluctuations in activity patterns.<a href="#cite_note-2">[2]</a>

While today monophasic sleep is the norm, historical analysis suggests that polyphasic nighttime sleep was common practice across societies before <a href="Industrialization" class="mw-redirect" title="Industrialization">industrialization</a>. Polyphasic sleep is common in many animals, and is believed to be the ancestral sleep state for mammals, although <a href="Simian" title="Simian">simians</a> are monophasic.<a href="#cite_note-8FDZB-3">[3]</a>

A common practice of biphasic sleep is a <a href="Nap" title="Nap">nap</a>, a short period of daytime sleep in addition to nighttime sleep. An example of involuntary polyphasic sleep is the <a href="Circadian_rhythm" title="Circadian rhythm">circadian rhythm</a> disorder <a href="Irregular_sleep-wake_syndrome" class="mw-redirect" title="Irregular sleep-wake syndrome">irregular sleep-wake syndrome</a>.

The term polyphasic sleep is also used by an online community that experiments with alternative sleeping schedules in an attempt to increase productivity.<a href="#cite_note-4">[4]</a> There is no scientific evidence that this practice is effective or beneficial.<a href="#cite_note-5">[5]</a>

<div class="mw-heading mw-heading2"><h2 id="Biphasic_sleep">Biphasic sleep</h2></div>

Biphasic sleep (also referred to as segmented sleep, or bimodal sleep) is a pattern of sleep which is divided into two segments, or phases, in a 24-hour period.

<div class="mw-heading mw-heading3"><h3 id="Single_nap_(siesta)">Single nap (siesta)</h3></div>

/* start https://en.wikipedia.org/ */

.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}

/* end https://en.wikipedia.org/ */

</style><div role="note" class="hatnote navigation-not-searchable">Further information: <a href="Siesta" title="Siesta">Siesta</a></div>

One classic cultural example of a biphasic sleep pattern is the practice of <a href="Siesta" title="Siesta">siesta</a>, which is a <a href="Nap" title="Nap">nap</a> taken in the early afternoon, often after the midday <a href="Meal" title="Meal">meal</a>.<a href="#cite_note-6">[6]</a> 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 <a href="Mediterranean_Basin" class="mw-redirect" title="Mediterranean Basin">Mediterranean</a> and <a href="Southern_Europe" title="Southern Europe">Southern Europe</a>. It is the traditional daytime sleep of <a href="China" title="China">China</a>,<a href="#cite_note-CzuK2-7">[7]</a> <a href="India" title="India">India</a>, <a href="South_Africa" title="South Africa">South Africa</a> , <a href="Italy" title="Italy">Italy</a>,<a href="#cite_note-cTn8A-8">[8]</a> <a href="Greece" title="Greece">Greece</a>, <a href="Spain" title="Spain">Spain</a> and, through Spanish influence, the <a href="Philippines" title="Philippines">Philippines</a> and many <a href="Hispanic_America" title="Hispanic America">Hispanic American</a> countries. In modern times, fewer Spaniards take a daily siesta, ostensibly due to more demanding work schedules.<a href="#cite_note-9">[9]</a>

<div class="mw-heading mw-heading3"><h3 id="Historical_"first_sleep"_and_"second_sleep"">Historical "first sleep" and "second sleep"</h3></div>

A separate biphasic sleep pattern is sometimes described as segmented sleep, involved sleeping in two phases, separated by about an hour of wakefulness. This pattern was common in preindustrial societies, and it was most common to sleep early ("first sleep"), wake around midnight, and return to bed later ("second sleep").<a href="#cite_note-Barron,_NYT_2016.03.31-10">[10]</a> Along with a nap in the day, it has been argued that this is the natural pattern of human sleep in long winter nights.<a href="#cite_note-pmid10607034-11">[11]</a><a href="#cite_note-bbc2012-12">[12]</a> A case has been made that maintaining such a sleep pattern may be important in regulating stress.<a href="#cite_note-bbc2012-12">[12]</a>

Historian <a href="A._Roger_Ekirch" class="mw-redirect" title="A. Roger Ekirch">A. Roger Ekirch</a> has argued that before the <a href="Industrial_Revolution" title="Industrial Revolution">Industrial Revolution</a>, interrupted sleep was dominant in Western civilization.<a href="#cite_note-Ekirch2001-13">[13]</a><a href="#cite_note-Ekirch2005-14">[14]</a> Ekirch asserts that the intervening period of wakefulness was used to pray<a href="#cite_note-acacoc-1908-15">[15]</a> and reflect,<a href="#cite_note-IriqL-16">[16]</a> and to interpret <a href="Dream" title="Dream">dreams</a>, 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 crime.<a href="#cite_note-Ekirch2005-14">[14]</a> He draws evidence from more than 500 references to a segmented sleeping pattern in documents from the ancient, medieval, and modern world.<a href="#cite_note-bbc2012-12">[12]</a> Other historians, such as Craig Koslofsky,<a href="#cite_note-mHP95-17">[17]</a> have endorsed Ekirch's analysis.

Ekirch suggests that it is due to the modern use of <a href="Electric_lighting" class="mw-redirect" title="Electric lighting">electric lighting</a> that most modern humans do not practice interrupted sleep.<a href="#cite_note-iq9Xt-18">[18]</a> Some have proposed that a sleep pattern based on the historical biphasic sleep schedule might be beneficial, but there is no widespread agreement on this.<a href="#cite_note-19">[19]</a>

A 2015 study of three non-industrial equatorial societies showed that all three experienced monophasic nighttime sleep,<a href="#cite_note-20">[20]</a> but the authors' conclusions were questioned by others.<a href="#cite_note-d439-21">[21]</a>

<div class="mw-heading mw-heading2"><h2 id="Experimental_schedules">Experimental schedules</h2></div>

<div class="mw-heading mw-heading3"><h3 id="Everyman_schedule">Everyman schedule</h3></div>

The Everyman schedule involves sleeping 3 hours during the night ("core sleep"), and taking three 20-minute naps during the day. This totals 4 hours of sleep in a 24-hour period.<a href="#cite_note-:0-22">[22]</a>

<div class="mw-heading mw-heading3"><h3 id="Uberman_schedule">Uberman schedule</h3></div>

The Uberman sleep schedule consists of a 30-minute nap every four hours, totaling 3 hours of sleep in a 24-hour period.<a href="#cite_note-:0-22">[22]</a>

Other variations of this sleep pattern involve 8 naps throughout the day, or 20-minute sleep intervals as opposed to 30 minutes.

<div class="mw-heading mw-heading3"><h3 id="Dymaxion_schedule">Dymaxion schedule</h3></div>

<a href="Buckminster_Fuller" title="Buckminster Fuller">Buckminster Fuller</a> described a regimen consisting of 30-minute naps every six hours. The short article about Fuller's nap schedule in <a href="Time_(magazine)" title="Time (magazine)">Time</a> in 1943, which referred to the schedule as "intermittent sleeping", says that he maintained it for two years, and notes that "he had to quit because his schedule conflicted with that of his business associates, who insisted on sleeping like other men."<a href="#cite_note-wSR3N-23">[23]</a>

This schedule is likely the most extreme type of polyphasic sleep schedule, totaling only two hours of sleep in a 24-hour period.<a href="#cite_note-24">[24]</a>

<div class="mw-heading mw-heading2"><h2 id="In_extreme_situations">In extreme situations</h2></div>

In crises and other extreme conditions, people may not be able to achieve the recommended seven to nine hours of sleep per day.<a href="#cite_note-25">[25]</a> Systematic napping may be considered necessary in such situations.

<a href="Claudio_Stampi" title="Claudio Stampi">Claudio Stampi</a>, as a result of his interest in long-distance <a href="Single-handed_sailing" title="Single-handed sailing">solo boat racing</a>, 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.<a href="#cite_note-grG5z-26">[26]</a> <a href="Scientific_American_Frontiers" title="Scientific American Frontiers">Scientific American Frontiers</a> (<a href="Public_Broadcasting_Service" class="mw-redirect" title="Public Broadcasting Service">PBS</a>) 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.<a href="#cite_note-MwYd0-27">[27]</a> Stampi has written about his research in his book <a href="Why_We_Nap%3A_Evolution%2C_Chronobiology%2C_and_Functions_of_Polyphasic_and_Ultrashort_Sleep" class="mw-redirect" title="Why We Nap: Evolution, Chronobiology, and Functions of Polyphasic and Ultrashort Sleep">Why We Nap: Evolution, Chronobiology, and Functions of Polyphasic and Ultrashort Sleep</a> (1992).<a href="#cite_note-0ikrG-28">[28]</a> In 1989 he published results of a field study in the journal <a href="Work_%26_Stress" title="Work & Stress">Work & Stress</a>, concluding that "polyphasic sleep strategies improve prolonged sustained performance" under continuous work situations.<a href="#cite_note-UdEbN-29">[29]</a> In addition, other long-distance solo sailors have documented their techniques for maximizing wake time on the open seas. One account documents the process by which a solo sailor broke his sleep into between six and seven naps per day. The naps would not be placed equiphasically, instead occurring more densely during night hours.<a href="#cite_note-TFTuI-30">[30]</a>

The <a href="United_States_armed_forces" class="mw-redirect" title="United States armed forces">U.S. military</a> has studied fatigue countermeasures. An Air Force report states:

/* start https://en.wikipedia.org/ */

.mw-parser-output .templatequote{overflow:hidden;margin:1em 0;padding:0 32px}.mw-parser-output .templatequotecite{line-height:1.5em;text-align:left;margin-top:0}@media(min-width:500px){.mw-parser-output .templatequotecite{padding-left:1.6em}}

/* end https://en.wikipedia.org/ */

</style><blockquote class="templatequote">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).<a href="#cite_note-3jOv0-31">[31]</a></blockquote>

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

<blockquote class="templatequote"> 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 rested.<a href="#cite_note-a2qSf-32">[32]</a>

</blockquote>

<a href="NASA" title="NASA">NASA</a>, in cooperation with the <a href="National_Space_Biomedical_Research_Institute" title="National Space Biomedical Research Institute">National Space Biomedical Research Institute</a>, has funded research on napping. Despite NASA recommendations that <a href="Astronaut" title="Astronaut">astronauts</a> 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 <a href="David_F._Dinges" title="David F. Dinges">David Dinges</a> of the <a href="University_of_Pennsylvania_School_of_Medicine" class="mw-redirect" title="University of Pennsylvania School of Medicine">University of Pennsylvania School of Medicine</a> 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 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 <a href="Working_memory" title="Working memory">working memory</a> benefited greatly. Naps in the individual subjects' biological daytime worked well, but naps in their nighttime were followed by much greater <a href="Sleep_inertia" title="Sleep inertia">sleep inertia</a> lasting up to an hour.<a href="#cite_note-M3dI0-33">[33]</a>

The <a href="Italian_Air_Force" title="Italian Air Force">Italian Air Force</a> (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 <a href="Electroencephalography" title="Electroencephalography">EEG</a> microsleeps." EEG <a href="Microsleep" title="Microsleep">microsleeps</a> 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 attention.<a href="#cite_note-AdS66-34">[34]</a>

<div class="mw-heading mw-heading2"><h2 id="Physiology">Physiology</h2></div>

The brain exhibits high levels of the <a href="Pituitary" class="mw-redirect" title="Pituitary">pituitary</a> <a href="Hormone" title="Hormone">hormone</a> <a href="Prolactin" title="Prolactin">prolactin</a> during the period of nighttime wakefulness, which may contribute to the feeling of peace that many people associate with it.<a href="#cite_note-Randall2012-35">[35]</a>

In his 1992 study "In short photoperiods, human sleep is biphasic", <a href="Thomas_Wehr" title="Thomas Wehr">Thomas Wehr</a> had seven 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 <a href="Sleep_debt" title="Sleep debt">sleep debt</a>. After this the subjects began to sleep much as people in pre-industrial times were claimed to have done. 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 asleep.<a href="#cite_note-pmid10607034-11">[11]</a>

Polyphasic sleep can be caused by <a href="Irregular_sleep-wake_syndrome" class="mw-redirect" title="Irregular sleep-wake syndrome">irregular sleep-wake syndrome</a>, a rare <a href="Circadian_rhythm_sleep_disorder" title="Circadian rhythm sleep disorder">circadian rhythm sleep disorder</a> which is usually caused by neurological abnormality, head injury or <a href="Dementia" title="Dementia">dementia</a>.<a href="#cite_note-48jry-36">[36]</a> Much more common examples are the sleep of human infants and of many animals. Elderly humans often have disturbed sleep, including polyphasic sleep.<a href="#cite_note-j0crZ-37">[37]</a>

In their 2006 paper "The Nature of Spontaneous Sleep Across Adulthood",<a href="#cite_note-fHlSx-38">[38]</a> Campbell and Murphy studied sleep timing and quality in young, middle-aged, and older adults. They found that, in <a href="Free-running_sleep" title="Free-running sleep">free-running</a> conditions, the average duration of major nighttime sleep was significantly longer in young adults than in the other groups. The paper states further:

<blockquote class="templatequote">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.</blockquote>

<ul><li><a href="Tahajjud" title="Tahajjud">Tahajjud</a></li>

<li><a href="Tikkun_Chatzot" title="Tikkun Chatzot">Tikkun Chatzot</a></li>

<li><a href="Watchkeeping" title="Watchkeeping">Watchkeeping</a></li></ul>

<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>

/* start https://en.wikipedia.org/ */

.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}

/* end https://en.wikipedia.org/ */

</style><div class="reflist">

/* start https://en.wikipedia.org/ */

.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("./mw/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("./mw/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("./mw/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("./mw/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}

/* end https://en.wikipedia.org/ */

</style><cite id="CITEREFMorinEspie2012" class="citation book cs1">Morin, Charles M.; Espie, Colin A. (2012). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=f6p2KGTXSNYC&pg=PA224">The Oxford Handbook of Sleep and Sleep Disorders</a>. Oxford University Press, USA. p. 224. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-0-19-537620-3</bdi>.</cite>

</li>

<li id="cite_note-2"><a href="#cite_ref-2">^</a> <a href="Why_We_Nap%3A_Evolution%2C_Chronobiology%2C_and_Functions_of_Polyphasic_and_Ultrashort_Sleep" class="mw-redirect" title="Why We Nap: Evolution, Chronobiology, and Functions of Polyphasic and Ultrashort Sleep">Stampi 1992</a>

</li>

<li id="cite_note-8FDZB-3"><a href="#cite_ref-8FDZB_3-0">^</a> <cite id="CITEREFCapelliniNunnMcNamaraPreston2008" class="citation journal cs1">Capellini, I.; Nunn, C. L.; McNamara, P.; Preston, B. T.; Barton, R. A. (1 October 2008). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2860325">"Energetic constraints, not predation, influence the evolution of sleep patterning in mammals"</a>. Functional Ecology. 22 (5): 847–853. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1111%2Fj.1365-2435.2008.01449.x">10.1111/j.1365-2435.2008.01449.x</a>. <a href="PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2860325">2860325</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/20428321">20428321</a>.</cite>

</li>

<li id="cite_note-4"><a href="#cite_ref-4">^</a> <cite class="citation magazine cs1"><a rel="nofollow" class="external text" href="https://time.com/5063665/what-is-polyphasic-sleep/">"People Are Sleeping in 20-Minute Bursts To Boost Productivity"</a>. Time. 30 January 2018. Retrieved 10 August 2023.</cite>

</li>

<li id="cite_note-5"><a href="#cite_ref-5">^</a> <cite id="CITEREFWeaverSlettenFosterGozal2021" class="citation journal cs1">Weaver, Matthew D.; Sletten, Tracey L.; Foster, Russell G.; Gozal, David; Klerman, Elizabeth B.; Rajaratnam, Shantha M. W.; Roenneberg, Till; Takahashi, Joseph S.; Turek, Fred W.; Vitiello, Michael V.; Young, Michael W.; Czeisler, Charles A. (June 2021). <a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.sleh.2021.02.009">"Adverse impact of polyphasic sleep patterns in humans: Report of the National Sleep Foundation sleep timing and variability consensus panel"</a>. Sleep Health. 7 (3): 293–302. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.sleh.2021.02.009">10.1016/j.sleh.2021.02.009</a>. <a href="ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/2352-7226">2352-7226</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/33795195">33795195</a>.</cite>

</li>

<li id="cite_note-6"><a href="#cite_ref-6">^</a> <cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.sleepfoundation.org/how-sleep-works/biphasic-sleep">"Biphasic Sleep: What It Is And How It Works"</a>. Sleep Foundation. 5 August 2021. Retrieved 15 January 2025.</cite>

</li>

<li id="cite_note-CzuK2-7"><a href="#cite_ref-CzuK2_7-0">^</a> <cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.sleep.org/articles/napping-around-the-world/">"Napping Around the World"</a>. Sleep.org. 21 December 2017. Retrieved 28 May 2019. <q>In China: Workers often take a break after lunch and put their heads on their desks for an hour-long nap. It's considered a Constitutional right.</q></cite>

</li>

<li id="cite_note-cTn8A-8"><a href="#cite_ref-cTn8A_8-0">^</a> <cite id="CITEREFFinzi2016" class="citation web cs1">Finzi, Jerry (23 May 2016). <a rel="nofollow" class="external text" href="http://www.grandvoyageitaly.com/1/post/2016/05/chiuso-means-closed-in-italy-the-midday-riposa-siesta.html">""Chiuso" means Closed in Italy: The Midday Riposa (Siesta), The Italian Siesta"</a>. GRAND VOYAGE ITALY. Retrieved 28 May 2019.</cite>

</li>

<li id="cite_note-9"><a href="#cite_ref-9">^</a> <cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://magazine.scu.edu/magazines/summer-2015/barcelona-siesta/">"Barcelona Siesta"</a>. Santa Clara Magazine. Retrieved 10 January 2025.</cite>

</li>

<li id="cite_note-Barron,_NYT_2016.03.31-10"><a href="#cite_ref-Barron,_NYT_2016.03.31_10-0">^</a> <cite id="CITEREFBarron2016" class="citation news cs1">Barron, Jesse (31 March 2016). <a rel="nofollow" class="external text" href="https://www.nytimes.com/2016/04/03/magazine/letter-of-recommendation-segmented-sleep.html">"Letter of Recommendation: Segmented Sleep"</a>. <a href="The_New_York_Times_Magazine" title="The New York Times Magazine">The New York Times Magazine</a>. Retrieved 16 May 2021.</cite>

</li>

<li id="cite_note-pmid10607034-11">^ <a href="#cite_ref-pmid10607034_11-0">a</a> <a href="#cite_ref-pmid10607034_11-1">b</a> <cite id="CITEREFWehr1992" class="citation journal cs1">Wehr, T. A. (June 1992). "In short photoperiods, human sleep is biphasic". Journal of Sleep Research. 1 (2): 103–107. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1111%2Fj.1365-2869.1992.tb00019.x">10.1111/j.1365-2869.1992.tb00019.x</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/10607034">10607034</a>.</cite>

</li>

<li id="cite_note-bbc2012-12">^ <a href="#cite_ref-bbc2012_12-0">a</a> <a href="#cite_ref-bbc2012_12-1">b</a> <a href="#cite_ref-bbc2012_12-2">c</a> <cite id="CITEREFHegarty2012" class="citation news cs1">Hegarty, Stephanie (22 February 2012). <a rel="nofollow" class="external text" href="https://www.bbc.co.uk/news/magazine-16964783">"The myth of the eight-hour sleep"</a>. <a href="BBC_News" title="BBC News">BBC News</a>.</cite>

</li>

<li id="cite_note-Ekirch2001-13"><a href="#cite_ref-Ekirch2001_13-0">^</a> <cite id="CITEREFEkirch2001" class="citation journal cs1">Ekirch, A. Roger (2001). "Sleep We Have Lost: Pre-industrial Slumber in the British Isles". <a href="The_American_Historical_Review" title="The American Historical Review">The American Historical Review</a>. 106 (2): 343–386. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.2307%2F2651611">10.2307/2651611</a>. <a href="JSTOR_(identifier)" class="mw-redirect" title="JSTOR (identifier)">JSTOR</a> <a rel="nofollow" class="external text" href="https://www.jstor.org/stable/2651611">2651611</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/18680884">18680884</a>.</cite>

</li>

<li id="cite_note-Ekirch2005-14">^ <a href="#cite_ref-Ekirch2005_14-0">a</a> <a href="#cite_ref-Ekirch2005_14-1">b</a> <cite id="CITEREFEkirch2005" class="citation book cs1">Ekirch, A. Roger (2005). <a rel="nofollow" class="external text" href="https://archive.org/details/atdaysclose00arog_0">At Day's Close: Night in Times Past</a>. W. W. Norton. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-0-393-34458-5</bdi>.</cite>

</li>

<li id="cite_note-acacoc-1908-15"><a href="#cite_ref-acacoc-1908_15-0">^</a> Hinds, William Alfred (1908). <a rel="nofollow" class="external text" href="https://archive.org/details/AmericanCommunitiesAndCo-operativeColonies/page/n375">American Communities and Co-operative Colonies</a> p 22 at the <a href="Internet_Archive" title="Internet Archive">Internet Archive</a>. "the followers of <a href="Conrad_Beissel" title="Conrad Beissel">Beissel</a> were wont to assemble for prayer and worship at midnight, the services lasting till one o'clock, when a second period of sleep till four was allowed."

</li>

<li id="cite_note-IriqL-16"><a href="#cite_ref-IriqL_16-0">^</a> Frances Quarles (London 1644), Enchirdion ch. 54

</li>

<li id="cite_note-mHP95-17"><a href="#cite_ref-mHP95_17-0">^</a> <cite id="CITEREFKoslofsky2011" class="citation book cs1">Koslofsky, C. M. (2011). "An early modern revolution". Evening's Empire: A History of the Night in Early Modern Europe. pp. 1–18. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1017%2FCBO9780511977695.001">10.1017/CBO9780511977695.001</a>. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>9780511977695</bdi>.</cite>

</li>

<li id="cite_note-iq9Xt-18"><a href="#cite_ref-iq9Xt_18-0">^</a> <cite id="CITEREFGamble2010" class="citation audio-visual cs1"><a href="Jessa_Gamble" title="Jessa Gamble">Gamble, Jessa</a> (2010). <a rel="nofollow" class="external text" href="http://www.ted.com/talks/jessa_gamble_how_to_sleep.html">Our natural sleep cycle</a>. TEDGlobal 2010, Oxford, England (video). TED Conferences, LLC. Retrieved 27 April 2014. <q>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.</q></cite>

</li>

<li id="cite_note-19"><a href="#cite_ref-19">^</a> <cite id="CITEREFThompson2022" class="citation web cs1">Thompson, Derek (27 January 2022). <a rel="nofollow" class="external text" href="https://www.theatlantic.com/ideas/archive/2022/01/medieval-sleeping-habits-insomnia-segmented-biphasic/621372/">"Can Medieval Sleeping Habits Fix America's Insomnia?"</a>. The Atlantic. Retrieved 5 October 2023.</cite>

</li>

<li id="cite_note-20"><a href="#cite_ref-20">^</a> <cite id="CITEREFYetishKaplanGurvenWood2015" class="citation journal cs1">Yetish, Gandhi; Kaplan, Hillard; Gurven, Michael; Wood, Brian; Pontzer, Herman; Manger, Paul R.; Wilson, Charles; McGregor, Ronald; Siegel, Jerome M. (2 November 2015). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4720388">"Natural sleep and its seasonal variations in three pre-industrial societies"</a>. Current Biology: CB. 25 (21): 2862–2868. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.cub.2015.09.046">10.1016/j.cub.2015.09.046</a>. <a href="ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1879-0445">1879-0445</a>. <a href="PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4720388">4720388</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/26480842">26480842</a>.</cite>

</li>

<li id="cite_note-d439-21"><a href="#cite_ref-d439_21-0">^</a> <cite id="CITEREFEkirch2016" class="citation journal cs1">Ekirch, A. Roger (2016). <a rel="nofollow" class="external text" href="https://academic.oup.com/sleep/article-pdf/39/3/715/13679929/aasm.39.3.715.pdf">"Segmented Sleep in Preindustrial Societies"</a> (PDF). Sleep. 39 (3): 715–716. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.5665%2Fsleep.5558">10.5665/sleep.5558</a>. <a href="ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1550-9109">1550-9109</a>. <a href="PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4763365">4763365</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/26888454">26888454</a>. Retrieved 30 March 2025.</cite>

</li>

<li id="cite_note-:0-22">^ <a href="#cite_ref-:0_22-0">a</a> <a href="#cite_ref-:0_22-1">b</a> <cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.sleepfoundation.org/how-sleep-works/polyphasic-sleep">"Polyphasic Sleep: Benefits and Risks"</a>. Sleep Foundation. 12 August 2021. Retrieved 15 January 2025.</cite>

</li>

<li id="cite_note-wSR3N-23"><a href="#cite_ref-wSR3N_23-0">^</a> <cite class="citation magazine cs1"><a rel="nofollow" class="external text" href="https://content.time.com/time/subscriber/article/0,33009,774680,00.html">"Science: Dymaxion Sleep"</a>. <a href="Time_(magazine)" title="Time (magazine)">Time</a>. 11 October 1943. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20160302155910/http://content.time.com/time/subscriber/article/0,33009,774680,00.html">Archived</a> from the original on 2 March 2016.</cite>

</li>

<li id="cite_note-24"><a href="#cite_ref-24">^</a> <cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://health.clevelandclinic.org/polyphasic-sleep">"Should You Try Polyphasic Sleep?"</a>. Cleveland Clinic. Retrieved 15 January 2025.</cite>

</li>

<li id="cite_note-25"><a href="#cite_ref-25">^</a> <cite id="CITEREFWatsonBadrBelenkyBliwise2015" class="citation journal cs1">Watson, Nathaniel F.; Badr, M. Safwan; Belenky, Gregory; Bliwise, Donald L.; Buxton, Orfeu M.; Buysse, Daniel; Dinges, David F.; Gangwisch, James; Grandner, Michael A.; Kushida, Clete; Malhotra, Raman K.; Martin, Jennifer L.; Patel, Sanjay R.; Quan, Stuart F.; Tasali, Esra (1 June 2015). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4434546">"Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society"</a>. Sleep. 38 (6): 843–844. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.5665%2Fsleep.4716">10.5665/sleep.4716</a>. <a href="ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0161-8105">0161-8105</a>. <a href="PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4434546">4434546</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/26039963">26039963</a>.</cite>

</li>

<li id="cite_note-grG5z-26"><a href="#cite_ref-grG5z_26-0">^</a> <cite id="CITEREFWanjek2007" class="citation web cs1">Wanjek, Christopher (18 December 2007). <a rel="nofollow" class="external text" href="http://www.livescience.com/7449-cheat-sleep-dreams.html">"Can You Cheat Sleep? Only in Your Dreams"</a>. LiveScience.</cite>

</li>

<li id="cite_note-MwYd0-27"><a href="#cite_ref-MwYd0_27-0">^</a> <cite class="citation episode cs1"><a rel="nofollow" class="external text" href="http://www.chedd-angier.com/frontiers/season1.html">"Catching catnaps, on season 1, episode 5"</a>. <a href="Scientific_American_Frontiers" title="Scientific American Frontiers">Scientific American Frontiers</a>. Chedd-Angier Production Company. 1990–1991. <a href="PBS" title="PBS">PBS</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20060101000000/http://www.pbs.org/saf/transcripts/transcript105.htm">Archived</a> from the original on 1 January 2006.</cite>

</li>

<li id="cite_note-0ikrG-28"><a href="#cite_ref-0ikrG_28-0">^</a> <cite id="CITEREFStampi2013" class="citation book cs1">Stampi, Claudio, ed. (2013). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=WI2-BwAAQBAJ&pg=PP1">Why We Nap: Evolution, Chronobiology, and Functions of Polyphasic and Ultrashort Sleep</a>. Springer Science & Business Media. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2F978-1-4757-2210-9">10.1007/978-1-4757-2210-9</a>. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-4757-2210-9</bdi>.</cite>

</li>

<li id="cite_note-UdEbN-29"><a href="#cite_ref-UdEbN_29-0">^</a> <cite id="CITEREFStampi1989" class="citation journal cs1">Stampi, Claudio (January 1989). "Polyphasic sleep strategies improve prolonged sustained performance: A field study on 99 sailors". <a href="Work_%26_Stress" title="Work & Stress">Work & Stress</a>. 3 (1): 41–55. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1080%2F02678378908256879">10.1080/02678378908256879</a>.</cite>

</li>

<li id="cite_note-TFTuI-30"><a href="#cite_ref-TFTuI_30-0">^</a> <cite id="CITEREFStampi2004" class="citation web cs1">Stampi, Claudio (12 June 2004). <a rel="nofollow" class="external text" href="http://www.sitesalive.com/ocl/private/04s/sleep/slp040608.html">"Rich Wilson's Sleep Patterns Prior to and During the Transat Race"</a>. Chronobiology Research Institute, Boston, Massachusetts.</cite>

</li>

<li id="cite_note-3jOv0-31"><a href="#cite_ref-3jOv0_31-0">^</a> <cite id="CITEREFCaldwell2003" class="citation book cs1">Caldwell, John A. (February 2003). <a rel="nofollow" class="external text" href="https://apps.dtic.mil/sti/pdfs/ADA413128.pdf">An Overview of the Utility of Stimulants as a Fatigue Countermeasure for Aviators</a> (PDF). Brooks AFB, Texas: United States Air Force Research Laboratory. p. 15. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20160825200406/http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ada413128">Archived</a> from the original on 25 August 2016.</cite>

</li>

<li id="cite_note-a2qSf-32"><a href="#cite_ref-a2qSf_32-0">^</a> <cite id="CITEREFRhodesGil2007" class="citation book cs1">Rhodes, Wayne; Gil, Valérie (17 January 2007). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20131228064318/http://www.tc.gc.ca/eng/innovation/tdc-publication-tp13960e-13960e-602.htm">Fatigue Management Guide for Canadian Marine Pilots – A Trainer's Handbook (TP 13960E)</a>. Transport Canada, Transportation Development Centre. Minimum Sleep Requirement. Archived from <a rel="nofollow" class="external text" href="http://www.tc.gc.ca/eng/innovation/tdc-publication-tp13960e-13960e-602.htm">the original</a> on 28 December 2013.</cite>

</li>

<li id="cite_note-M3dI0-33"><a href="#cite_ref-M3dI0_33-0">^</a> <cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://science.nasa.gov/science-news/science-at-nasa/2005/03jun_naps/">"NASA-supported sleep researchers are learning new and surprising things about naps"</a>. NASA Science: Science News. <a href="NASA" title="NASA">NASA</a>. 3 June 2005.</cite>

</li>

<li id="cite_note-AdS66-34"><a href="#cite_ref-AdS66_34-0">^</a> <cite id="CITEREFPorcuCasagrandeFerraraBellatreccia1998" class="citation journal cs1">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. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.3109%2F00207459809000648">10.3109/00207459809000648</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/9845015">9845015</a>.</cite>

</li>

<li id="cite_note-Randall2012-35"><a href="#cite_ref-Randall2012_35-0">^</a> <cite id="CITEREFRandall2012" class="citation book cs1">Randall, David K. (2012). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=4vgQqcSY3hwC&pg=PT18">"2. Light My Fire"</a>. Dreamland: Adventures in the Strange Science of Sleep. W. W. Norton. pp. 17–18. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-0-393-08393-4</bdi>.</cite>

</li>

<li id="cite_note-48jry-36"><a href="#cite_ref-48jry_36-0">^</a> <cite id="CITEREFZeeMichael_V._Vitiello2009" class="citation journal cs1">Zee, Phyllis C.; Michael V. Vitiello (June 2009). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2768129">"Circadian Rhythm Sleep Disorder: Irregular Sleep Wake Rhythm Type"</a>. Sleep Med Clin. 4 (2): 213–218. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.jsmc.2009.01.009">10.1016/j.jsmc.2009.01.009</a>. <a href="PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2768129">2768129</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/20160950">20160950</a>.</cite>

</li>

<li id="cite_note-j0crZ-37"><a href="#cite_ref-j0crZ_37-0">^</a> <cite id="CITEREFMori1990" class="citation journal cs1">Mori, A. (January 1990). <a rel="nofollow" class="external text" href="https://doi.org/10.3143%2Fgeriatrics.27.12">"Sleep disturbance in the elderly"</a>. Nippon Ronen Igakkai Zasshi (Abstract in English). 27 (1): 12–7. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.3143%2Fgeriatrics.27.12">10.3143/geriatrics.27.12</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/2191161">2191161</a>.</cite>

</li>

<li id="cite_note-fHlSx-38"><a href="#cite_ref-fHlSx_38-0">^</a> <cite id="CITEREFCampbellMurphy2007" class="citation journal cs1">Campbell, Scott S.; Murphy, Patricia J. (March 2007). "The nature of spontaneous sleep across adulthood". Journal of Sleep Research. 16 (1): 24–32. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1111%2Fj.1365-2869.2007.00567.x">10.1111/j.1365-2869.2007.00567.x</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/17309760">17309760</a>.</cite>

</li>

</ol></div></div>

<div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2></div>

<ul><li><cite id="CITEREFBraff2022" class="citation news cs1">Braff, Danielle (13 February 2022). <a rel="nofollow" class="external text" href="https://www.nytimes.com/2022/02/12/style/segmented-sleep.html">"Meet Me at 3 A.M. For a Cup of Coffee"</a>. <a href="The_New_York_Times" title="The New York Times">The New York Times</a>. <a href="ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0362-4331">0362-4331</a>. <a href="OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/1645522">1645522</a>. Retrieved 13 February 2022.</cite></li>

<li><cite class="citation book cs1"><a href="Daniel_Everett" title="Daniel Everett">Everett, Daniel Leonard</a> (2008). <a rel="nofollow" class="external text" href="https://archive.org/details/dontsleeptherear00ever">Don't Sleep, There are Snakes: Life and Language in the Amazonian Jungle</a>. Pantheon Books. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-0-307-37779-1</bdi>. <a href="OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/430034945">430034945</a>.</cite></li>

<li><cite class="citation web cs1">Gorvett, Zaria (7 January 2022). <a rel="nofollow" class="external text" href="https://www.bbc.com/future/article/20220107-the-lost-medieval-habit-of-biphasic-sleep">"The forgotten medieval habit of 'two sleeps'"</a>. BBC Future.</cite></li>

<li><cite class="citation book cs1">Koslofsky, Craig (2011). <a rel="nofollow" class="external text" href="https://archive.org/details/eveningsempirehi0000kosl">Evening's Empire</a>. Cambridge: Cambridge University Press. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1017%2Fcbo9780511977695">10.1017/cbo9780511977695</a>. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-0-511-97769-5</bdi>. <a href="OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/1149044844">1149044844</a>.</cite></li>

<li><cite class="citation book cs1">Verdon, Jean (2002). Night in the Middle Ages. Translated by Holoch, George. University of Notre Dame Press. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>0-268-03655-1</bdi>. <a href="OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/905792043">905792043</a>.</cite></li>

<li><cite class="citation book cs1"><a href="Jeff_Warren" title="Jeff Warren">Warren, Jeff</a> (2007). <a rel="nofollow" class="external text" href="https://archive.org/details/headtrip00jeff/page/63/mode/2up">"The Watch"</a>. The Head Trip: Adventures on the Wheel of Consciousness. New York: Random House. pp. 63–98. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-0-679-31408-0</bdi>. <a href="OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/1149271015">1149271015</a>.</cite></li></ul>

<div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div>

<ul><li><cite class="citation web cs1">Zimmermann, Tim (1 April 2005). <a rel="nofollow" class="external text" href="https://www.outsideonline.com/health/training-performance/miles-go-i-sleep/">"Miles to Go Before I Sleep"</a>. Outside Online.</cite></li>

<li><a rel="nofollow" class="external text" href="https://polysleep.org/wiki/Main_Page">Polyphasic Sleep Wiki</a></li></ul>

/* start https://en.wikipedia.org/ */

.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}

/* end https://en.wikipedia.org/ */

</style><style data-mw-deduplicate="TemplateStyles:r1236075235">

/* start https://en.wikipedia.org/ */

.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}

/* end https://en.wikipedia.org/ */

</style></div><div role="navigation" class="navbox" aria-labelledby="Sleep_and_sleep_disorders127" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><style data-mw-deduplicate="TemplateStyles:r1239400231">

/* start https://en.wikipedia.org/ */

.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}

/* end https://en.wikipedia.org/ */

</style><div id="Sleep_and_sleep_disorders127" class="nowrap" style="font-size:114%;margin:0 4em"><a href="Sleep" title="Sleep">Sleep</a> and <a href="Sleep_disorder" title="Sleep disorder">sleep disorders</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Stages of <a href="Sleep_cycle" title="Sleep cycle">sleep cycles</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist nowrapitems" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Rapid_eye_movement_sleep" title="Rapid eye movement sleep">Rapid eye movement (REM)</a></li>

<li><a href="Non-rapid_eye_movement_sleep" title="Non-rapid eye movement sleep">Quiescent sleep</a></li>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Electroencephalography" title="Electroencephalography">Brain waves</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist nowrapitems" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Alpha_wave" title="Alpha wave">Alpha wave</a></li>

<li><a href="Delta_wave" title="Delta wave">Delta wave</a></li>

<li><a href="Gamma_wave" title="Gamma wave">Gamma wave</a></li>

<li><a href="K-complex" title="K-complex">K-complex</a></li>

<li><a href="Mu_wave" title="Mu wave">Mu rhythm</a></li>

<li><a href="PGO_waves" title="PGO waves">PGO waves</a></li>

<li><a href="Sensorimotor_rhythm" title="Sensorimotor rhythm">Sensorimotor rhythm</a></li>

<li><a href="Sleep_spindle" title="Sleep spindle">Sleep spindle</a></li>

<li><a href="Theta_wave" title="Theta wave">Theta wave</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Sleep_disorder" title="Sleep disorder">Sleep disorders</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist nowrapitems" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Oral_and_maxillofacial_pathology" title="Oral and maxillofacial pathology">Anatomical</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Mouth_breathing" title="Mouth breathing">Mouth breathing</a></li>

<li><a href="Sleep_apnea" title="Sleep apnea">Sleep apnea</a>

<ul><li><a href="Catathrenia" title="Catathrenia">Catathrenia</a></li>

<li><a href="Central_hypoventilation_syndrome" title="Central hypoventilation syndrome">Central hypoventilation syndrome</a></li>

<li><a href="Obesity_hypoventilation_syndrome" title="Obesity hypoventilation syndrome">Obesity hypoventilation syndrome</a></li>

<li><a href="Obstructive_sleep_apnea" title="Obstructive sleep apnea">Obstructive sleep apnea</a></li>

<li><a href="Periodic_breathing" title="Periodic breathing">Periodic breathing</a></li></ul></li>

<li><a href="Snoring" title="Snoring">Snoring</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Dyssomnia" title="Dyssomnia">Dyssomnia</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Excessive_daytime_sleepiness" title="Excessive daytime sleepiness">Excessive daytime sleepiness</a></li>

<li><a href="Hypersomnia" title="Hypersomnia">Hypersomnia</a></li>

<li><a href="Insomnia" title="Insomnia">Insomnia</a></li>

<li><a href="Kleine%E2%80%93Levin_syndrome" title="Kleine–Levin syndrome">Kleine–Levin syndrome</a></li>

<li><a href="Narcolepsy" title="Narcolepsy">Narcolepsy</a></li>

<li><a href="Idiopathic_hypersomnia" title="Idiopathic hypersomnia">Idiopathic hypersomnia</a></li>

<li><a href="Night_eating_syndrome" title="Night eating syndrome">Night eating syndrome</a></li>

<li><a href="Nocturia" title="Nocturia">Nocturia</a></li>

<li><a href="Sleep_state_misperception" title="Sleep state misperception">Sleep state misperception</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><div style="display: inline-block; line-height: 1.2em; padding: .1em 0; line-height: 1.15em;"><a href="Circadian_rhythm_sleep_disorder" title="Circadian rhythm sleep disorder">Circadian rhythm disorders</a></div></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Advanced_sleep_phase_disorder" title="Advanced sleep phase disorder">Advanced sleep phase disorder</a></li>

<li><a href="Cyclic_alternating_pattern" title="Cyclic alternating pattern">Cyclic alternating pattern</a></li>

<li><a href="Delayed_sleep_phase_disorder" title="Delayed sleep phase disorder">Delayed sleep phase disorder</a></li>

<li><a href="Irregular_sleep%E2%80%93wake_rhythm" class="mw-redirect" title="Irregular sleep–wake rhythm">Irregular sleep–wake rhythm</a></li>

<li><a href="Non-24-hour_sleep%E2%80%93wake_disorder" title="Non-24-hour sleep–wake disorder">Non-24-hour sleep–wake disorder</a></li>

<li><a href="Shift_work_sleep_disorder" title="Shift work sleep disorder">Shift work sleep disorder</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Parasomnia" title="Parasomnia">Parasomnia</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Bruxism" title="Bruxism">Bruxism</a></li>

<li><a href="Nightmare_disorder" title="Nightmare disorder">Nightmare disorder</a></li>

<li><a href="Night_terror" title="Night terror">Night terror</a></li>

<li><a href="Periodic_limb_movement_disorder" title="Periodic limb movement disorder">Periodic limb movement disorder</a></li>

<li><a href="Rapid_eye_movement_sleep_behavior_disorder" title="Rapid eye movement sleep behavior disorder">Rapid eye movement sleep behavior disorder</a></li>

<li><a href="Sleepwalking" title="Sleepwalking">Sleepwalking</a></li>

<li><a href="Sleep_driving" class="mw-redirect" title="Sleep driving">Sleep driving</a></li>

<li><a href="Sleep-talking" title="Sleep-talking">Sleep-talking</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Benign phenomena</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Dream" title="Dream">Dreams</a>

<ul><li><a href="Lucid_dream" title="Lucid dream">Lucid dreams</a></li></ul></li>

<li><a href="Exploding_head_syndrome" title="Exploding head syndrome">Exploding head syndrome</a></li>

<li><a href="Hypnic_jerk" title="Hypnic jerk">Hypnic jerk</a></li>

<li><a href="Hypnagogia" title="Hypnagogia">Hypnagogia</a> / <a href="Sleep_onset" title="Sleep onset">Sleep onset</a></li>

<li><a href="Hypnopompia" title="Hypnopompia">Hypnopompia</a></li>

<li><a href="Sleep_paralysis" title="Sleep paralysis">Sleep paralysis</a></li>

<li><a href="Sleep_inertia" title="Sleep inertia">Sleep inertia</a></li>

<li><a href="Somnolence" title="Somnolence">Somnolence</a></li>

<li><a href="Nocturnal_clitoral_tumescence" title="Nocturnal clitoral tumescence">Nocturnal clitoral tumescence</a></li>

<li><a href="Nocturnal_penile_tumescence" title="Nocturnal penile tumescence">Nocturnal penile tumescence</a></li>

<li><a href="Nocturnal_emission" title="Nocturnal emission">Nocturnal emission</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Sleep_medicine" title="Sleep medicine">Treatment</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Sleep_diary" title="Sleep diary">Sleep diary</a></li>

<li><a href="Sleep_hygiene" title="Sleep hygiene">Sleep hygiene</a></li>

<li><a href="Sleep_induction" title="Sleep induction">Sleep induction</a>

<ul><li><a href="Hypnosis" title="Hypnosis">Hypnosis</a></li>

<li><a href="Lullaby" title="Lullaby">Lullaby</a></li></ul></li>

<li><a href="Somnology" title="Somnology">Somnology</a>

<ul><li><a href="Polysomnography" title="Polysomnography">Polysomnography</a></li></ul></li>

<li><a href="Sleep_surgery" title="Sleep surgery">Sleep surgery</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Sleep_medicine" title="Sleep medicine">Sleep medicine</a></li>

<li><a href="Behavioral_sleep_medicine" title="Behavioral sleep medicine">Behavioral sleep medicine</a></li>

<li><a href="Sleep_study" title="Sleep study">Sleep study</a></li>

<li><a href="Melatonin" title="Melatonin">Melatonin</a></li>

<li><a href="Neuroscience_of_sleep" title="Neuroscience of sleep">Neuroscience of sleep</a></li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Daily life</th><td class="navbox-list-with-group navbox-list navbox-even hlist nowrapitems" style="width:100%;padding:0"><div style="padding:0 0.25em">

<li><a href="Daybed" title="Daybed">Daybed</a></li>

<li><a href="Four-poster_bed" title="Four-poster bed">Four-poster bed</a></li>

<li><a href="Futon" title="Futon">Futon</a></li>

<li><a href="Hammock" title="Hammock">Hammock</a></li>

<li><a href="Mattress" title="Mattress">Mattress</a></li>

<li><a href="Sleeping_bag" title="Sleeping bag">Sleeping bag</a></li></ul></li>

<li><a href="Bedding" title="Bedding">Bedding</a></li>

<li><a href="Bedroom" title="Bedroom">Bedroom</a></li>

<li><a href="Bedtime" title="Bedtime">Bedtime</a>

<ul><li><a href="Bedtime_procrastination" title="Bedtime procrastination">Procrastination</a></li>

<li><a href="Bedtime_story" title="Bedtime story">Story</a></li></ul></li>

<li><a href="Biphasic_and_polyphasic_sleep" class="mw-redirect" title="Biphasic and polyphasic sleep">Biphasic and polyphasic sleep</a></li>

<li><a href="Chronotype" title="Chronotype">Chronotype</a></li>

<li><a href="Circadian_rhythm" title="Circadian rhythm">Circadian rhythm</a></li>

<li><a href="Comfort_object" title="Comfort object">Comfort object</a></li>

<li><a href="Dream_diary" title="Dream diary">Dream diary</a></li>

<li><a href="Microsleep" title="Microsleep">Microsleep</a></li>

<li><a href="Nightwear" title="Nightwear">Nightwear</a></li>

<li><a href="Power_nap" title="Power nap">Power nap</a></li>

<li><a href="Second_wind_(sleep)" title="Second wind (sleep)">Second wind</a></li>

<li><a href="Siesta" title="Siesta">Siesta</a></li>

<li><a href="Sleep_and_breathing" title="Sleep and breathing">Sleep and breathing</a></li>

<li><a href="Sleep_and_creativity" title="Sleep and creativity">Sleep and creativity</a></li>

<li><a href="Sleep_and_learning" title="Sleep and learning">Sleep and learning</a></li>

<li><a href="Sleep_and_memory" title="Sleep and memory">Sleep and memory</a></li>

<li><a href="Sleep_deprivation" title="Sleep deprivation">Sleep deprivation</a> / <a href="Sleep_debt" title="Sleep debt">Sleep debt</a></li>

<li><a href="Sleeping_while_on_duty" title="Sleeping while on duty">Sleeping while on duty</a></li>

<li><a href="Sleepover" title="Sleepover">Sleepover</a></li></ul>

</div></td></tr></tbody></table></div>

</div><div><div class="zim-footer">

This article is issued from <a class="external text" title="Last edited on 2025-08-01" href="https://en.wikipedia.org/wiki/?title=Polyphasic_sleep&oldid=1303691067">Wikipedia</a>. The text is available under <a class="external text" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en">Creative Commons Attribution-Share Alike 4.0</a> unless otherwise noted. Additional terms may apply for the media files.

</div>

</div></div>

</div>

</main>

</div>

</body></html>