Is Segmented (Polyphasic) Sleep Healthy – 6 Things That You Should Know

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Have you ever thought about the time you spend sleeping and wondered if there’s a more efficient way to occupy the nighttime hours?

Scientists, high performers, and bio-hackers have all been exploring the idea of segmented sleep as a way to both get more done and improve the overall quality of their rest.

There’s been a lot of debate in recent years about whether or not this type of schedule is natural, healthy, and even how to do it given the hectic pace of modern society.

If you’ve been hearing about the idea of segmented or polyphasic sleeping, this segmented sleep guide will help you decide whether you should give it a try, along with recommendations on how to modify your schedule.

What is Segmented Sleep?

Segmented sleep is also referred to as “polyphasic sleep.” Instead of sleeping in one large chunk of time during the night, your rest takes place in two or more sessions.

The word itself almost requires no definition as poly means many or more than one. Phasic refers to phases, and you probably already know that a phase is a time period or stage. Therefore, people who engage in polyphasic sleep, are going to bed in segments.

For example, someone who has this type of schedule may go to bed at 9 p.m., and then wake up around midnight. They’ll stay awake for a couple of hours, then fall back to bed until the morning. In this example, there are only two phases, which is considered biphasic or bimodal, but depending on the way it’s practiced, those who engage in segmented sleeping behavior could rest in as many as eight different periods in a 24-hour cycle.

This method of sleeping, although considered by many to be unhealthy today, is the way that our ancestors slept until the late 19th century.

woman sleeping in a cozy bed with a book next to her

The History Behind It

Historians believe that this way of sleeping is how humans naturally evolved, and there are written accounts of this way of resting that go back nearly 3,000 years, where polyphasic sleeping is referenced in Homer’s Odyssey.

People across cultures and from all walks of life slept this way. The “in between” time was considered sacred. Some would use this time to pray or visit neighbors, while others used it for sexual relations with their partners.

According to the book At Day’s Close: Night in Times Past, doctors in France during the 16th century referred to this time window as dorveille, which when translated, means a dreamlike semi-conscious state. These doctors advised patients that the time between sleeping periods was ideal for conception. They even went as far as to claim that couples would “have more enjoyment” and “do it better.”

The leading theory behind this recommendation is that as darkness came, we would get drowsy and tired from long, laborious days. Instead of trying to muster up the energy for a roll in the hay, it would be better for both parties to take a nap first. Then, after a few hours of shuteye, couples felt refreshed and ready to enjoy each other’s physical company. Makes perfect sense, right?

Though this slumber style seems like fun, it began to fall out of favor in the late 17th century. The upper classes in urban areas were the first to eschew this practice. Most likely this was due to having more leisure time and social opportunities, which created the idea of nightlife.

Over the next couple hundred years, the practice faded further, and by 1920, society as a whole had abandoned the idea of a first and second sleep.

Find Out More: The History of Human Sleep

Segmented Sleep & Sleep Architecture

In a typical seven to nine-hour bedtime block, there will be distinct stages that make up a cycle. A full sleep cycle has five stages ranging from light rest to REM (rapid eye movement), which is the time when we dream. Interspersed within that are multiple periods of SWS or slow-wave sleep.

Instead of being repeated in brief periods throughout the night, those who engage in segmented sleep will experience a large dose of it in their first three hours of rest. Because this stage is associated with deep and restorative sleeping, being able to experience this stage fully and all once often results in people reporting that they feel better-rested.

When the person begins their second stage of sleeping, they’ll spend much of it in REM. The result is a more vivid remembrance of dreams, as well as a higher likelihood of lucid dreaming.

image of a messy bed

How It Affects Hormones

Prolactin is a hormone that is most famous for enabling female mammals to produce breast milk. However, it also has a role in sleeping that’s not widely known.

Biologists have discovered that it’s more beneficial to release a surge of prolactin at night rather than have a steady stream of it coursing through the body for the entire day. It also influences sex hormones like testosterone and estrogen. When people rest in segments, they’re able to better regulate the production of prolactin, having higher concentrations in the wee hours of the morning.

The result of polyphasic sleep, then, is an increased libido and a better balance of hormones.


Some of humanities’ most celebrated authors have referred to the benefits of segmented sleep, including Jane Austen, Charles Dickens, and Leo Tolstoy, to name a few.

This quiet in-between time is almost like getting a few bonus hours per day to accomplish more. Here are some key advantages:

  • Relish quiet time without demands of work, family or social distractions
  • Use the time to meditate and reflect
  • Enjoy intimacy with a partner
  • Potentially increase chances of conception
  • Those who are religious view it as a time to communicate with God
  • Catch up on chores so that you can begin the day ahead of schedule
  • Get more quality rest in two periods than you may get in one, uninterrupted block
  • Increase dream recall and the chance to experience lucid dreaming

Learn More: How Geniuses Sleep?


With all of those advantages, why isn’t everyone sleeping in shifts? Well, it turns out that modern society complicates things. Here are some disadvantages to changing your schedule:

  • If you use any artificial light during this time (a TV for example), it can disrupt your internal clock
  • It may be difficult to fall back to bed

Frequently Asked Questions

What is a triphasic sleep schedule?

This type of schedule involves three naps during a 24-hour period, hence the prefix of “tri.” These napping times coincide well with our natural energy peaks. For example, the first rest period would be the longest, and it should occur just after dusk when melatonin production spikes. Another sleep session would follow it before dawn, and then you would naturally wake up with the sun.

The third nap would take place in the afternoon, between the hours of 1 p.m. and 4 p.m., when our bodies naturally tend to feel an afternoon energy dip.

woman fell asleep while reading a book

Is polyphasic sleep healthy?

It depends on who you ask. Many scientists caution against it, especially if you can’t avoid exposure to artificial light in the in-between period. This schedule could also be a challenge to maintain because most modern humans don’t fall asleep at dusk.

To make polyphasic sleep part of a healthy lifestyle, you’d have to commit to sticking the schedule consistently. While one late night out won’t harm you too much, if it’s a regular habit, you won’t get the full effect.

What is the best sleep schedule for segmented rest?

There are approximately nine different schedules you could experiment with to get segmented rest. Some of them are as extreme as brief naps throughout the day that could result in as many as eight sleeping periods. Imagine trying to explain that to your boss!

The most natural way of doing things tends to be the healthiest. As humans, we evolved to sleep in two periods: one at dusk and one a few hours before dawn. Therefore, if you’re looking to try this type of schedule, we recommend starting with that and then modifying to suit your lifestyle.


Whether you decide to adapt your bedtime schedule to separate phases or remain a monophasic (single phase) sleeper, you may find comfort in knowing that waking up in the middle of the night is considered normal, and even healthy.

So, the next time you’re staring at the ceiling at 2 a.m., try not to think of what you’re experiencing as insomnia. Instead, it has a much more magical term: dorveille.

Sources and References:

  1. What Is Segmented Sleep and Is It Healthy? –
  2. What is segmented sleep? Actigraphy field validation for daytime sleep and nighttime wake. –

More Reading:

Our team covers as many areas of expertise as we do time zones, but none of us started here as a so-called expert on sleep. What we do share is a willingness to ask questions (lots of them), seek experts, and dig deep into conventional wisdom to see if maybe there might be a better path towards healthy living. We apply what we learn not only to our company culture, but also how we deliver information to our over 12.7M readers.

Sleep research is changing all the time, and we are 100% dedicated to keeping up with breakthroughs and innovations. You live better if you sleep better. Whatever has brought you here, we wish you luck on your journey towards better rest.

Sleep Advisor