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Biphasic Sleep – Is Sleeping Twice Better For Us?

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This simply means sleeping twice during the 24 hours. It means having a shorter rest during the night and sleeping again during the daytime. Siesta is something that comes to the mind immediately when we talk about sleeping twice in a day. Biphasic sleep differs a bit.

In siesta, people sleep for an hour or more during the day time. However, in biphasic sleep, people may have a short nap. Nonetheless, whether you have a quick nap or long rest, both would be regarded as biphasic.

Such sleep should not be confused with polyphasic sleep. Polyphasic sleepers are those who sleep multiple time during the day.

Is biphasic sleep normal?

Amazingly enough, if we look at human history, it seems that biphasic sleep is even more natural than monophasic sleep we are used to nowadays. It would be completely wrong to say that practices like siesta were present in some cultures.

Research indicates that in pre-industrial age biphasic sleep schedule was not only prevalent in Europe; it was part of many other cultures. In the middle east, Africa, Asia, Australia, Latin America, everywhere people use to sleep at least twice in 24 hours. On the other hand, monophasic sleep schedule was a rare thing.

This culture of sleeping more than once was common even in cold countries like England and Scandinavian nations.

Interestingly enough, this culture of having a second sleep remained widespread in many parts of the world even in the 19th century. It is especially true for places where artificial illumination came later.

Few texts indicate that in some cultures people even ate when they liked. Thus in some tribal regions, people would get up at midnight to have food and sit near the fire.

There is enough literary and scientific proof that the culture of sleeping once in 24 hours is entirely new. It is something that emerged with artificial lightning, industrialization, and adaptation of modern lifestyle.

Further, the early literature shows that biphasic sleep does not necessarily mean sleeping once in a nighttime and having a second sleep during the mid-day. In some cultures, people would retire early, and then get up at midnight to do some leisurely tasks. After a couple of hours, they would go to bed again, sleeping until dawn.

Can biphasic sleep hurt health?

Biphasic sleep seems to be safe for health, as suggested by clinical evidence and old sleep habits of humans. Indeed, many suggest that biphasic sleep is more natural than monophasic sleep.

Some researchers think that lack of biphasic sleep may explain insomnia in many people. Some persons are genetically made to have a nap during the day.

Some of the studies suggest that having a short nap of about 20 minutes may be enough to improve performance. Short naps can improve alertness and have a refreshing effect. However, if rest is prolonged, then benefits are unclear, as longer naps result in deep sleep.

In one systemic review, it was reported that a short nap might be useful for those working in night shifts. Just 20 minutes of nap is enough to reduce sleepiness and improve the feeling of wellness.

Is biphasic sleep same as polyphasic sleep schedule

Surely not, these are different sleep patterns. Polyphasic sleep is interrupted; it is segmented sleep, polyphasic sleep is about multiple naps in 24 hours. Biphasic sleep pattern means strictly twice in a day, once in a night, and once during the day.

Examples of biphasic sleep schedule

In biphasic sleep pattern, you aim to sleep twice. One long sleep in the night with multiple non-REM and REM sleep cycles, and one shorter nap during the day.

Short nap sleep schedule

You sleep about six hours during the night and have a quick 20-minute nap during the day. It is vital not to exceed 20 minutes to avoid slipping into a deep sleep or even REM Sleep. A nap should be short, so that not to disturb circadian rhythm.

Long nap sleep schedule

In this sleep pattern you sleep for about five hours during the night. However, daytime sleep schedule in longer, of about 1.5 hours. The daytime sleep aims to go through one sleep cycle, non-REM and REM sleep.

In conclusion, we can say that such sleep is natural and healthy. Follow this schedule to sleep like your ancestors. It was how we slept before the industrial revolution, in pre-modern time. It would help you to make better use of wakefulness. It makes waking hours extra productive.


In conclusion, we can say that such sleep is natural and healthy. Follow this schedule to sleep like your ancestors. It was how we slept before the industrial revolution, in pre-modern time. It would help you to make better use of wakefulness. It makes waking hours extra productive.

Additional resources

  1. Lovato N, Lack L. The effects of napping on cognitive functioning. In: Kerkhof GA, Dongen HPA van, eds. Progress in Brain Research. Vol 185. Elsevier; 2010:155-166. doi:10.1016/B978-0-444-53702-7.00009-9
  2. Wehr TA. In short photoperiods, human sleep is biphasic. Journal of Sleep Research. 1992;1(2):103-107. doi:10.1111/j.1365-2869.1992.tb00019.x
  3. Banks MJ and S. Humans Used to Sleep in Two Shifts, And Maybe We Should Do It Again. ScienceAlert. https://www.sciencealert.com/humans-used-to-sleep-in-two-shifts-maybe-we-should-again. Accessed November 6, 2018.
  4. Ruggiero JS, Redeker NS. Effects of Napping on Sleepiness and Sleep-Related Performance Deficits in Night-Shift Workers: A Systematic Review. Biological Research For Nursing. 2014;16(2):134-142. doi:10.1177/1099800413476571

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