The "Four-Hour Sleep Method"? Is it really reliable to imitate animals in sleeping?

"Turning around the red pavilion, lowering the beautiful window, shining on the sleepless" (Song Dynasty, Su Shi's "Water Melody: When Will the Bright Moon Appear"), insomnia has plagued mankind from ancient times to the present, and humans have been trying to solve the mystery of sleep.

Did you know? Although almost all organisms need sleep, there are significant differences in sleep patterns between species and even between individuals of the same species. Compared with humans, rodents have shorter total sleep durations and frequent sleep phase changes, following a polyphasic sleep pattern .

What is polyphasic sleep?

Polyphasic sleep is the process of dividing your daily sleep into two or more segments , rather than just sleeping in one large segment at night (the most common way of sleeping in modern society).

Our earliest understanding of polyphasic sleep began with animals. Polyphasic sleep is very common in the animal kingdom, with more than 86% of mammals showing a typical polyphasic sleep rhythm, which is also considered to be the sleeping state of mammal ancestors.

Think about your cats and dogs.

Is it also sleeping for a while and waking up for a while?

In the human world, adults usually sleep only once a day for 6 to 8 hours. This sleeping pattern is called monophasic sleep . A long sleep of 6 to 7 hours a day plus a nap of about 0.5 hours is called biphasic sleep .

Polyphasic sleep is the process of splitting the single sleep that humans are accustomed to into multiple sleep cycles (more than 2) to reduce the overall sleep time. It also has a famous name abroad - "Da Vinci sleep".

According to legend, in order to save time for artistic creation, Leonardo da Vinci slept once every 4 hours, for 15 to 20 minutes each time. In this way, he only slept about 2 hours a day. This not only saved time but also kept him energetic. This is the "4-hour sleep method" mentioned by Zhang Chaoyang.

Image source: Video screenshot

On this basis, we have derived a series of polyphasic sleep methods.

For example, the "Everyman Sleep Plan" is about dividing sleep into a main sleep stage and three short sleep fragments. Sleep for 5 to 6 hours at night, and take a nap in any 3 stages during the day, with each stage lasting 30 minutes.

The "Ubrman Sleep Plan" divides a day into 6 equal parts, with 6 sleeps a day, 30 minutes each time, which adds up to 30x6=180 minutes, a total of 3 hours. This sleep plan claims to compensate for lack of sleep by increasing REM sleep (rapid eye movement sleep).

In addition to monophasic sleep, there are many different sleep modes (dark is sleep) | typewhiter.com

Although some humans claim that they follow sleeping methods such as "Da Vinci Sleep Method" and "Everyman Sleep", these are only differences between individuals. There is currently little information to prove that polyphasic sleep was once a common practice for all human beings.

However, biphasic sleep was very common throughout history .

In his book At Day's Close: Night in Times Past, Virginia Tech history professor Roger Ekirch notes that in pre-industrial Western cultures, waking up in the middle of the night was common, if not customary.

Back then, with schedules dictated by the sun rather than clocks and electric lights, people might have gone to bed earlier; instead of a short, continuous eight-hour sleep, their rest periods might have been longer, perhaps consisting of two shorter sleep periods interspersed with periods of wakefulness.

During this waking time, people would do some household chores, such as mending by firelight, combing wool, or even chopping wood and doing farm work in the moonlight. At midnight, when they finished their work, they would return to bed and sleep until dawn.

Polyphasic sleep, is it worth it for humans?

Since most animals in nature sleep polyphasically, and historical data show that humans also have the habit of biphasic sleep, can modern humans today also sleep polyphasically?

There are different views on this.

Some people believe that the polyphasic sleep pattern is the original sleep pattern of human beings. However, with the advent of the Industrial Revolution and the emergence of artificial light sources, humans began to override the natural darkness , reducing the time of sleep, thus forming a monophasic sleep pattern.

Daniel Buysse, professor of psychiatry, medicine, and clinical and translational medicine at the University of Pittsburgh, said that because we are always compressing our sleep time, the two processes of sleep (intrinsic rhythm and circadian rhythm) are "mixed together". Given more time, the two processes may be separated, allowing us to wake naturally according to our internal sleep rhythm. In fact, the wakefulness between the several sleep periods may also play a survival function.

Others believe that human infants also have a distinct polyphasic sleep rhythm , but when they grow up and enter society, they are forced to sleep in a monophasic manner due to various factors. Some researchers have pointed out that there is little reason to believe that the human sleep/wake system will evolve in a completely different way. Psychologist Claudio Stampi believes that polyphasic sleep can effectively improve sustained athletic performance under sleep deprivation.

However, modern medicine does not recommend polyphasic sleep.

Modern medical research believes that a person's full night of sleep is generally divided into several parts: light sleep (stages N1 and N2), deep sleep (stage N3), and rapid eye movement sleep (REM). These parts constitute the sleep cycle. Each sleep cycle is marked by the end of the REM stage. One cycle is about 1.5 hours, and there are about 4 to 6 sleep cycles in a whole night.

Comparison of sleep expert manual staging and model staging Source: References

Normal sleep is a process of periodic decline like waves. The deeper people sleep, the deeper they fall asleep. Some people are "easy to wake up" and fall asleep again soon after waking up, but they have enough sleep time. According to the polyphasic sleep theory, as long as they have REM periods between two or more awakenings, it will not cause any harm to the body.

But in fact, as long as the number of awakenings during sleep reaches 2-3 times, it will cause obvious distress to people. At least from the perspective of the cycle changes of sleep EEG, it is impossible to break up a full night of sleep into 6 15-minute REM periods.

Doctors suggest that if you really cannot guarantee sleep at night, regular short naps can make up for the sleep debt and restore energy to a certain extent, but this is only a temporary substitute when it is absolutely necessary. Long-term lack of sleep or implementing the "Everyman Sleep Plan" or "Da Vinci Sleep Method" regardless of personal circumstances will lead to a series of changes in the human body .

A study found that people who frequently wake up during the night in their 30s and 40s are more than twice as likely to have cognitive problems a decade later.

The study on "the cause of cancer caused by staying up late" confirmed through experiments for the first time that reversing day and night is a human carcinogen

Perhaps there is no specific human sleep pattern, and the above are just individual differences. Boyce said that because sleep is affected by the natural and social environment, sleep patterns may vary greatly from person to person, and may also vary in different regions and seasons. "In general, I don't think there is a so-called one human sleep pattern," he said. "Adaptability is the main feature."

Sleep, there are still many mysteries waiting to be uncovered

In recent years, thanks to the innovation and progress of research methods, we have revealed the role of specific types of neurons in different brain regions in sleep-wake regulation.

The brain does not "shut down" during sleep, but rather "switches its working mode": many brain areas are still in an excited state during sleep, and even the maintenance of sleep itself depends on the normal operation of sleep-related circuits.

However, there are still many mysteries about sleep that remain unsolved. For example, why do we need sleep? What is the main function of sleep? What is the function of dreams? These questions have not yet been answered.

On the other hand, sleep disorders have become a problem all over the world, and more and more people are suffering from sleep disorders. On March 18, 2024, the China Sleep Research Society released the "2024 Chinese Residents' Sleep White Paper". The survey showed that the overall sleep quality of Chinese residents is poor, and waking up early and having difficulty falling asleep are the main sleep problems. In addition, the length of sleep at night is generally short, with an average sleep time of 6.75 hours. For most people, it is difficult to sleep through the night.

Hopefully, in the future, we can uncover more mysteries about sleep so that everyone can enjoy adequate and effective sleep.

References:

59. Polyphasic Sleep Wiki (polysleep.org)
60. link.springer.com/chapter/10.1007/978-1-4757-2210-9_1
61. Roger Ekirch, Professor of History at Virginia Tech, At Day's Close: Night in Times Past
62. onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2869.2007.00567.x
63. Da Vinci's Sleep Method - People's Political Consultative Conference Network (rmzxb.com.cn)
64. Hu Kailei, Chen Jingxia, Zhang Pengwei, Xue Wen, Xie Jia. Multimodal physiological time-frequency feature extraction network for accurate sleep staging[J]. Journal of Biomedical Engineering, 2024, 41(01): 26-33.
65. Brown RE, Basheer R, McKenna JT, Strecker RE, McCarley RW. Control of sleep and wakefulness. Physiol Rev. 2012 Jul;92(3):1087-187.
66. China Sleep Research Society "White Paper on Chinese Residents' Sleep in 2024" Author: Wang Juan

Popular science content editor, popular science author, headline quality content creator

Editor: Dong Xiaoxian