Naps are sometimes considered lazy, but evidence throughout human history suggests that nappers might have the right idea.
Unlike traditional sleep, in which you sleep for a solid six to nine hours, polyphasic sleep involves dividing your sleep time into several short periods instead, supplemented by 20-minute naps during the day.
Most polyphasic sleepers tend to spend less time asleep, between two and seven hours in total per day, and advocates of the method say that your body will quickly adjust and learn to enter REM sleep more comfortably.
How Does it Work?
The theory behind polyphasic sleep rests on the fact that only deep or dreaming sleep is restful, and light sleep is just an intermediate phase between wakefulness and deep sleep.
Approximately 65% of every eight-hour sleep window consists of light sleep, which polyphasic sleep enthusiasts consider wasteful and unnecessary. Instead, polyphasic sleep aims to increase the amount of REM and slow-wave sleep.
REM, or rapid eye movement, is the stage of sleep where you dream and recover most of your mental capacity. It’s considered essential, and REM sleep deprivation leads to the body falling into REM more quickly during recovery sleep.
Lack of R.E.M sleep over the long term results in hallucinations, anxiety, irritability, and problems with concentration.
The second critical stage of sleep is slow-wave sleep, where the body performs several important immune and hormone functions. People in slow-wave sleep are much harder to wake, and there is little brain activity overall.
Different animals have different types of sleep. Humans tend to be monophasic or biphasic sleepers, sleeping for either one extended sleep period or two slightly shorter sleep periods every day.
However, other animals, such as rats, are natural polyphasic sleepers that cycle between SWS and wake states without even going into REM.
Humans under extremely stressful conditions, such as astronauts, special ops personnel, and open-ocean yacht racers, all start using polyphasic sleep to cope with their extreme conditions.
The History of Polyphasic Sleep
While we accept the idea that monophasic sleep is the norm, there’s a lot of evidence suggesting that biphasic sleep and polyphasic sleep were the predominant way of sleeping in humanity’s past.
There are several allusions in literature, such as Charles Dicken’s Barnaby Rudge, which describes “first” and “second sleep,” a mode of sleeping still popular in Spain and Italy in the form of the siesta.
The term “polyphasic sleep” was coined by J.S. Szymanski in 1920 when he noted that several mammalian species cycle between rapid bouts of sleep and activity per day. Subsequent studies have found that over 86% of all mammals exhibit polyphasic sleep patterns, mainly in response to an extreme need for vigilance for survival.
Many scientists still believe that sleep patterns are primarily dependent on two main biological processes that are common in all mammals, and likely even most vertebrates.
One of the most significant factors in sleep patterns is body mass, with smaller animals being more likely to exhibit polyphasic sleep. Deviations from this trend are usually due to predation, latitude, and food availability.
The other likely explanation for polyphasic sleep is that it’s incredibly useful for particular environmental factors, rather than an innate biological drive.
According to a study conducted by Thomas Wehr, humans return to a biphasic sleep mode when light is limited to 10 hours, instead of the ordinary 16.
In humans, polyphasic sleep strategies appear to prolong performance where monophasic sleep is impossible. However, these studies often examine people under extreme conditions of continuous work, where naps are disproportionately useful.
How to Polyphasic Sleep
Developing a polyphasic sleep routine requires a lot of discipline and planning. Unfortunately, our normal circadian rhythms don’t line up with polyphasic sleep, so you’ll need to retrain your body to sleep when you need to.
While there are no hard and fast rules for adopting a polyphasic sleep pattern, there are several guidelines on how to make the switch.
Quick note: Most polyphasic sleepers recommend starting with switching from a monophasic to a biphasic sleep pattern.
Typical biphasic sleep patterns reduce the healthy core night sleep to around six hours, and then include a nap during the day, usually around lunch-time to mid-afternoon. The nap should only last between 30 minutes to an hour, and you should feel refreshed after waking up.
Once you’re comfortable with that pattern, shorten your main night phase and add in a nap during the day. Keep shortening your main night period and adding naps until you have a polyphasic schedule you’re comfortable maintaining.
One of the most commonly recommended polyphasic sleep schedules is the Everyman Two. This schedule consists of one core sleep period of around four to five hours at night and two naps spread throughout the day.
Proponents of this schedule say it’s flexible enough to accommodate any sort of lifestyle, and you can always sneak in a third nap if you’re feeling unusually tired.
The most extreme form of polyphasic sleep is the Ubermans sleep schedule (illustrated above), which consists only of 20-minute naps, spaced evenly throughout the day. The traditional schedule calls for six naps, one every four hours, resulting in only two hours of sleep per day.
Crazy right? Just two hours of sleep per day!
What are the Benefits of Polyphasic Sleep?
Proponents of polyphasic sleep suggest that it comes with many benefits, including:
What are the Dangers of Polyphasic Sleep?
The main danger of enforced polyphasic sleep is sleep deprivation, which can affect every facet of your life.
Sleep deprivation from chronic sleep restriction can result in a decreased immune response, delayed reaction times, impair cognition, and increased risk of chronic conditions such as diabetes and obesity.
Even people who recommend polyphasic sleep recommend that people with the following conditions avoid trying to polysleep:
What Do the Experts Say?
While there is plenty of evidence regarding the efficacy of napping or short-term polyphasic sleep in extreme, continuous work circumstances, there are very few studies that examine the long-term effects of the practice.
Peter Woźniak, a scientist whose research interests include the optimization of sleep, is very skeptical about polyphasic sleeping. He believes…
Polyphasic sleep is impossible without sleep deprivation, as it’s the sleep deprivation that drives the body into a rapid state of REM sleep.
As such, he suggests that it’s an unsustainable state that may be useful for short bursts but is harmful in the longer term.
Conclusion: Who Should Polyphasic Sleep?
Polyphasic sleep may offer several significant benefits to particular people.
If you’re incredibly busy throughout the day and just need more time in the day, switching to polysleep can likely help maximize your productive time at the expense of more sleep.
Polyphasic sleep appears to be useful for people who have to work continuously, such as oil rig workers, firefighters, or ocean-yacht racers. Adopting a polyphasic sleep schedule helps maintain the performance that may otherwise be affected by lack of sleep.
However, while polyphasic sleep may offer significant short-term benefits, the science of long-term polyphasic sleep schedules is a bit less sound.
Many sleep scientists have concerns that prolonged sleep deprivation from enforced sleeping habits may have a detrimental effect on your health.
You probably shouldn’t try polyphasic sleep, especially those who are chronically ill, have substance abuse problems, or have poor diets that put them at risk of metabolic disease. Switching up your sleep schedule in these instances may do more harm than good.