If you’re the type of person who has never been able to sleep straight through the night or if you want to enhance your productivity by sleeping less, the polyphasic sleep schedule might be tempting. Afterall, it has been used by the United States military, NASA, Canadian marine pilots, and the Italian Air Force. But before you change up your sleep habits, consider the consequences of disrupting your sleep schedule. Here’s everything you need to know about this non-traditional way of sleeping.
Polyphasic sleep refers to a method of sleeping that includes sleeping multiples times per day or at least more than two instead of the traditional eight hours straight at night. It is also known as divided or segmented sleep. It includes taking a nap or a shorter period of sleep between the hours of 9 am and 9 pm in addition to your usual night time sleep (1).
The term dates back to the early 20th century when psychologist J.S. Szymanski was observing daily fluctuations in his patient’s activity patterns (2). According to Doctor Szymanski, polyphasic sleep does not mean that the person follows a particular sleep cycle. It occurs when there is a circadian rhythm disorder such as irregular sleep-wake syndrome. The circadian rhythm is your natural sleep cycle. It dictates when you fall asleep at night, how long you sleep, and when you wake up.
Irregular sleep-wake syndrome occurs as a result of neurological retardation, dementia or a head injury. Other examples of polyphasic sleep include the sporadic patterns of infants and some animals. Older adults may experience polyphasic sleep by breaking up their sleep periods throughout the day and night. Finally, some people intentionally avoid sleep to be more productive.
In modern times, the term polyphasic sleep refers to a group of people who practice alternative sleeping schedules to get more done during the day. If you know someone who claims they will “sleep when they die,” they might be more likely to practice polyphasic sleep by sleeping as little as possible. Research suggests that some of the greatest minds in the world used polyphasic sleep schedules to invest more time in their work, such as Napoleon, Nikola Telsa, and Leonardo da Vinci (1).
In some cases, it’s not always possible for a person to obtain eight hours of sleep at night. Pilots and military members may need to break up their sleep patterns to meet the demands of their job. When this occurs, the person may need to experiment with regular napping to keep their performance levels up. The United States military uses polyphasic sleep to counteract fatigue by having its members engage in regular napping. Research from the United states army found that each nap should be at least 45 minutes long, but longer naps such as two hours long are better (1). Shorter naps need to be taken more often than longer naps to achieve a total duration of eight hours each day.
The Canadian marine pilots use a similar technique to keep performance levels up during extreme circumstances. Research shows that even 10 to 20 minute long naps at regularly scheduled intervals throughout the day can help alleviate some of the symptoms of sleep deprivation (1). Researchers warn that performance levels during shorter naps can never be used as a replacement for being fully rested. In other words, regular napping might be okay for awhile, but it shouldn’t be used long term.
NASA has spent a lot of time researching napping. NASA recommends that their astronauts sleep a full eight hours each day while in space, but they recognize that sleep habits may be disrupted due to the nature of the profession. Because of this, napping may be warranted. Professor David Dinges of the University of Pennsylvania School of Medicine has spent a lot of time researching systematic napping. He studies anchor sleep, which is a term that describes a person who sleeps for either four to eight hours with no naps or they take daily naps of around 2.5 hours long (1).
Professor Dinges' research shows that longer naps were better for improving cognitive function. Specifically, longer naps improved working memory, basic alertness, and vigilance. People who napped in the daytime were less likely to experience sleep inertia than when they napped at night. It was noted that sleep inertia lasted for up to an hour when the subjects were woken up during their night time naps. Sleep inertia occurs when you feel confused or disoriented for a few minutes while transitioning from the sleep to wake cycle.
The Italian air force also tested polyphasic sleeping on its pilots who worked the night shift and occasionally worked during the day, too. The pilots were asked to perform two hours of work followed by four hours of sleep. This cycle was repeated four times within a 24 hour period. Results showed that the pilots only slept during the last three rest periods. They also increased the duration of their sleep in these last three rest sessions.
According to the study, the pilot’s total sleep time was substantially reduced when compared to a standard eight-hour sleep shift that most people get at night. But they maintained healthy vigilance levels as shown by the lack of microsleeps on an EEG (1). Microsleeps occur when a person who is sleep deprived falls asleep for 30 second periods during the day. During microsleep, a person’s eyes may be open, but their brain is essentially asleep as it doesn’t receive messages from the external environment. Individuals who do not get enough rest may experience microsleeps throughout the day. The condition is especially dangerous for anyone operating a plane or vehicle.
Unless you’re in a position where you absolutely must practice polyphasic sleep, it’s probably best that you try to sleep seven to nine hours a night. The standard sleep cycle lasts from 90 to 110 minutes long. The average healthy adult goes through about five or six of these sleep cycles each night. Together, they help you recover from the day. Your body needs proper amounts of sleep to detox its brain cells of hazardous waste materials, improve cognitive function, and prevent disease.
Comprising your sleep needs puts you at an increased risk of obesity, diabetes, and heart disease. It also makes you unreliable behind the wheel and more likely to get into an accident. Sleep loss makes you function at levels lower than you normally would, which can compromise work and athletic performance. Sleep is needed to sustain brain health and ward off dementia, Alzheimer’s and Parkinson’s diseases. It’s in your best interest to get in the full amount of rest for your age group every night and save napping for special occasions.
While the average person who has access to regular sleeping habits should stick to their nighttime routine, some research indicates that polyphasic sleep can be a beneficial option for those who don’t. According to a 2012 report, polyphasic sleep has various psychological effects on a person. The author of the study concluded that polyphasic sleep might be as beneficial for performance as monophasic sleep, or sleeping one time per day. But timing and duration of naps are important as short-term memory may be affected (3).
A 2014 article published in Psychology Today also supported polyphasic sleep cycles as an alternative to the traditional eight hours of sleep at night. According to the article, sleeping eight hours at night is stressful for people who are unable to achieve this goal. It also ignores historical sleeping patterns as well (4). A 2007 study published in the Journal of Sleep stated that most animals on Earth use polyphasic sleep schedules (5).
The article makes the point that everyone has different sleep needs. While one person might do well on a polyphasic sleep schedule, another might crash their car. Research shows that as much as three percent of the population can survive just fine on a few hours of sleep without any harmful side effects (4).
Other research shows that until the invention of electricity, most people slept in segments of two periods of sleep. They would go to bed and stay asleep for three to five hours, wake up for one to two hours, and fall back asleep for another three to five hours. It wasn’t until after artificial light was created that literature began referring to terms such as “deep sleep.” Light is one of the main factors for determining sleep. So it’s very possible that before there were television and computers to keep us awake late at night, our ancestors broke up their sleep into two or more segments to protect against predators.
Another article published in Psychiatric Times stated that broken up sleep is more natural than we think. In the article, Doctor Walter Brown of Brown Medical School suggested that waking up in the middle of the night is not a sign of a sleep disorder or insomnia. He stated that the general public and some sleep specialists seem to think that getting eight hours of sleep each night is a birthright and anyone who gets less than that must have something wrong with them. This causes people who wake up in the middle of the night to turn to prescription medications to fall back asleep, but it may just be their normal sleep cycle kicking in (6). Doctor Brown suggests that they will fall back asleep naturally in an hour or so if they don’t fight it.
While all this talk of sleeping in segments to increase productivity is exciting, some research suggests that you shouldn’t believe all the hype just yet. A 2012 article stated that there is no such thing as adjusting to a sleep schedule that is out of sync no matter how long you keep it. Severe sleep deprivation causes a person to go into a recovery sleep when they do finally sleep, which is characterized by the increasing forces of the slowest brainwaves. In other words, your body is fighting for survival (7).
Some people think that they can get more done in one day by cheating sleep. Maybe you’ll be successful at it for awhile, but the risks associated with long term sleep deprivation are not pretty. Before trying polyphasic sleep, ask yourself why you are doing this. If you’re a college student and need to spend more time studying, consider that this approach to sleep might be okay for a few years, but you’ll want to adopt a normal sleep schedule as soon as possible. Also consider that sleeping enhances memory and brain function, which is better for test taking than cramming the night before.
Staying up late to work might seem like a tempting way to get things done while others sleep. Keep in mind that your body is naturally in tune with light and dark. When the sun goes down, your body naturally produces melatonin, which is a hormone that makes you feel sleepy. Your brain stops making melatonin or makes a minimal amount of it in the morning when exposed to daylight. While you might not go to sleep and wake up exactly with the sunrise and sunset, it’s probably best not to try to shorten your sleep schedule. Doing so can throw off your circadian cycle, which has a snowball effect on your other biological processes as well.
Think of your body as a finely tuned clock. All metabolic processes run in sync with each other. When you throw one off, you’re essentially throwing them all off. Messing with your sleep schedule when you don’t have to may also affect your metabolism, insulin resistance, and risk of disease. Some research suggests it even reduces longevity.
If your job or a health condition requires you to sleep in broken up periods, the best thing to do is practice smart polyphasic sleeping habits. This means your napping schedule should be finely tuned between performance and rest. Don’t try to go too long without sleep and be sure not to operate a vehicle until you know how polyphasic sleeping affects you.
Although no two people have the same sleep needs, polyphasic sleep isn’t something you should try long term. Doing so may affect your cognitive abilities as well as increase your risk of certain diseases. Sleep deprivation is linked to emotional outbursts and performance mistakes, making you less attractive to an employer. Unless you’re forced to, it’s best to aim for seven to nine hours of sleep each night even if you wake up for a few hours in between.