This one stretch of sleep is what sleep specialists call monophasic sleep. We’re taught it’s not only the best kind of sleep but the norm for how people are meant to rest.
But monophasic sleep isn’t the only option. For many people, especially those in countries where siestas are common, sleep occurs in two segments throughout the day — typically a long stretch at night supplemented by a nap in the day. This is known as biphasic sleep.
And then there’s polyphasic sleep, which involves sleeping in multiple shorter bouts throughout the day and night. It was practiced by our ancestors and is sometimes used by young people cramming for exams or looking to maximize time awake for various reasons. Those who deploy it say the sleep pattern has numerous benefits, including increasing productivity, alertness, and creativity during waking hours while also allowing more time for self-care and even better dream recall; however, experts warn that polyphasic sleep that deprives you of that seven-to-nine-hour total can be detrimental.
If your overnight sleep isn’t working for you, whether due to medical conditions, work demands, sleep disruptions by family members, or other needs, the polyphasic sleep pattern may be a solution for you. We asked the experts for the pros, cons, and basic science of sleeping in shorter spurts. Here’s what they had to say.
What is polyphasic sleep?
Polyphasic sleep is a sleep pattern that fragments sleep into multiple (three or more) short segments spaced across the 24-hour day. Infants and some animals sleep this way, as well as our hunter-gatherer ancestors. It’s thought that most of us were polyphasic sleepers before the Industrial Revolution and the advent of electricity. Back then, it was believed that people would awaken overnight to work by the light of the full moon.
Polyphasic sleep isn’t one-size-fits-all. There are four distinct types, each of which varies based on the number and length of naps or sleep sessions. But for the most part, they all severely restrict consolidated nighttime sleeping.
1. Dymaxion sleep schedule
A term invented by inventor Buckminster Fuller, the word "dymaxion" blends dynamic, maximum, and tension for a word that means getting maximal output from minimal energetic input. Accordingly, this approach is the most sleep-suppressed of all the polyphasic sleep patterns, calling for taking a 30-minute nap four times a day (every six hours) for a total of just two hours of sleep.
2. Uberman sleep schedule
Adapted from dymaxion, this still-restrictive sleep pattern relies on a quicker 20-minute nap increment — the recommended length of a power nap — with a more frequent cadence of every four hours instead of every six. The Uberman schedule ultimately totals the same two hours of sleep for every 24-hour period.
3. Everyman sleep schedule
This popular form of polyphasic sleep involves a three-hour chunk of overnight sleep followed by three 20-minute naps spread over the course of the day. All in all, followers get about four hours of sleep in a 24-hour period.
4.Triphasic sleep schedule
With this sleep pattern, you split the day into three chunks of eight hours, spending about six-and-a-half hours of each segment awake and completing one full sleep cycle to end the segment. The sleep cycles typically happen after dusk, before dawn, and in the afternoon. If each cycle averages 90 minutes, you accumulate approximately four-and-a-half hours of total sleep per day.
The problem with polyphasic sleep
Proponents of polyphasic sleep say sleeping in short bouts optimizes time in deep sleep (also known as slow-wave sleep or NREM 3) as well as rapid eye movement or REM sleep. They advocate focusing on these two of the four stages of sleep because deep sleep is the most restorative sleep and supports memory consolidation and healthy immune functioning; REM is important for mood regulation, concentration, and allowing the brain to process new information.
Typically deep sleep accounts for about 20% of your overnight sleep and REM for about 25%; for an overnight monophasic sleeper, more deep sleep occurs at the outset of your sleep, with REM occurring in longer stretches in the time shortly before awakening.
Polyphasic sleep fans claim that napping at the points of time when deep sleep or REM sleep might occur based on circadian rhythm can help you more heavily concentrate your sleep in those stages.
A literature review published in the journal Sleep Health, however, found no evidence to support those claims, instead pointing to several studies that directly refute them. One study compared an eight-hour consolidated sleep schedule to a three-hour polyphasic one and found that those who slept in a consolidated chunk had more REM and slow-wave sleep than those in the polyphasic group.
“This [polyphasic sleep] does not maximize time in REM and slow-wave sleep at all, and likely results in deprivation of all sleep stages, including these,” emphasizes Michael Grandner, Ph.D., an associate professor of psychiatry at the University of Arizona College of Medicine and director of the university’s Behavioral Sleep Medicine Clinic. “All stages of sleep are important, and this strategy represents a fundamental misunderstanding of how sleep works.”
Experts also thwart the notion of other purported benefits, such as increased productivity, greater creativity, and improved mood.
“Countless studies show that sleep deprivation ultimately undermines productivity,” says Dr. Chester Wu, a psychiatrist and sleep medicine specialist. “Due to the potential for sleep deprivation, polyphasic sleep can impair cognitive function, memory, mental health, and learning abilities.”
A study of cloistered monks and nuns who routinely had to rise from sleep at midnight for a two-to-three-hour-long prayer service found that they reported more memory lapses than those who had consolidated sleep.
In another study, researchers looked at the sleeping patterns of medical students and found that those who used a polyphasic system of sleep were the least likely to pass their midterm exams, while those who were biphasic sleepers were most likely to pass.
And the medical journals are full of studies — including this one on adolescents — showing that suboptimal sleep is associated with a number of mental health conditions, including depression and anxiety.
Health effects of too little sleep
Experts are quick to point out that when you skimp on sleep, you can impact your performance, memory, mood, and physical health.
Research shows that sleep deprivation even after a few nights, can be detrimental. Fatigue can stimulate cortisol production (the stress hormone), which can increase inflammation in the body, putting you at a greater risk for a variety of health complications, including diabetes and high blood pressure.
“Severe sleep restriction, for a relatively well-rested person, is not always unsafe for one to two days,” says Grandner. “We have circadian alertness rhythms that can help us get through the day, even if we are sleep-deprived. However, if someone severely restricts [their sleep] for more than a couple of days and/or they don't start out from a very well-rested position, then those one to two days of sleep restriction can cause catastrophic outcomes like injuries, accidents, etc. In terms of health, those effects will take more time to develop, though healthy people can start looking prediabetic after even just a few days of severe sleep restriction.”
How to try polyphasic sleep
As a prolonged practice, the experts say that it’s not a great idea to transition to long-term polyphasic sleep. But sometimes, your schedule won’t permit anything other than sleeping in snatches.
“If your schedule demands that you do something like this for a couple of days, get the best sleep you can for the one-to-two weeks beforehand,” says Grandner. “Bank that period of great sleep so that you come at it from a place of strength. Then, during the period where you are sleep deprived, you should be mostly OK for a day or two, but be careful about engaging in any safety-sensitive activities, especially at night when your biological drive to sleep is highest.”
And if you decide to supplement a shortened sleep schedule with naps, do so carefully, cautions Wu.
“If you can’t meet your full sleep need at night, napping during the day can be an effective way to pay back sleep debt,” he says. Once you’re ready to resume longer-term sleep, though, plan to cut back on naps, limiting them to 90 minutes tops. “While taking a longer nap every day is better than missing out on sleep altogether, it doesn’t have the same benefits as getting a full night’s sleep during the night. Plus, you’ll wake up feeling groggy and may struggle to sleep that night.”