What is Biphasic Sleep?

A person who sleeps at two different times a day has a biphasic sleep pattern. Sleeping at night and taking a nap during the day is an example of biphasic sleep. Biphasic sleep may also be referred to as divided, diphasic, segmented, or bimodal sleep.

When we think about getting a good night’s sleep, we usually think about sleeping for a single period of 8-hours. Unfortunately, work schedules, family obligations, health conditions, random events, and our sleep environment can make it difficult to get a straight 8-hours of sleep. Often, we turn to sleeping twice a day (i.e., sleeping at night and taking a daytime nap) to help us cope. Fundamentally, sleeping two separate times within 24-hours is a biphasic sleep pattern, which is a form of segmented or divided sleep.

Sleeping at night and taking a nap during the day is an example of biphasic sleep.

Monophasic Sleepers by Nature

Most of us are monophasic sleepers; that is, we sleep continuously for one 6- to 8-hour period every 24-hours. When we wake up, we start our day and keep moving until it is time for bed again. Monophasic sleep usually involves sleeping for 6- to 8-hours. Even though monophasic sleep is thought to be the most common sleep pattern, biphasic and polyphasic sleep patterns are also common for various reasons.

Forms of Biphasic Sleep

When speaking of biphasic sleep, you may also hear the terms bimodal, diphasic, segmented, interrupted sleep, or divided sleep. Biphasic sleep also has several different forms.


Nighttime Sleep with a Supplemental Daytime Nap


One form of biphasic sleep is often referred to as “short nap” biphasic sleep. This pattern occurs when you take a short nap in the middle of the day, around 20 minutes, and then sleep again for about 6 hours each night. A second term used to describe biphasic sleep is known as “long nap” biphasic sleep. This pattern takes place when a sleeper takes about a 1 to 1.5-hour nap in the middle of the day and then sleeps around 5 hours each night.


Interrupted Sleep


Biphasic sleep that takes the form of interrupted sleep is as simple as the name suggests. This third form of biphasic sleep is when sleep goes interrupted. For example, if you wake up in the middle of the night (e.g., to go to the bathroom) and then go back to sleep, you have an interrupted biphasic sleep pattern. While these two different periods of sleep were only briefly separated, your sleep was interrupted and you slept during two different periods.


Biphasic vs. Polyphasic Sleep

Both biphasic and polyphasic sleep are forms of segmented or divided sleep patterns. Biphasic and polyphasic sleep patterns differ because biphasic sleep involves sleeping twice in a 24-hour period, while polyphasic sleep is when someone sleeps more than twice in a 24-hour period. These interrupted sleep patterns may be a sign of underlying sleep issues.

Causes of Biphasic Sleep

There are many potential causes of biphasic sleep. For some, a biphasic sleep pattern could come more naturally than a monophasic sleep pattern. Some people may need a nap during the day because they are suffering from sleep deprivation caused by several different factors. Sleep deprivation could be caused by underlying health conditions, such as sleep apnea, insomnia, restless leg syndrome, or sleep walking, could make it difficult to stay asleep and wake up feeling rested. Environmental factors, such as a noisy or distracting sleep environment could also cause sleep deprivation. Finally, lifestyle choices, such as drinking caffeine too late or night-time snacking could interfere with sleep and lead to sleep deprivation. These are just a few examples of what may cause a biphasic sleep pattern.


Thankfully, biphasic sleep is not necessarily a cause for concern. It is possible to have a biphasic sleep pattern without any serious health complications. In fact, it may be more natural for some people and others may even choose to have a biphasic sleep pattern because they feel more productive. The biphasic sleep pattern was actually quite popular until recent years, but is still used greatly in some cultures like the Spanish “siesta” (a siesta is when someone leaves work to have lunch at home and take a nap during the day, then go back to work). However, health complications can occur if your sleep is interrupted often, and you regularly experience sleep deprivation.

Avoiding Biphasic Sleep

Switching from a biphasic sleep pattern to a monophasic sleep pattern can be difficult because it might require addressing all of the factors that can cause a biphasic sleep pattern. Each person has different factors affecting their sleep patterns, so a one size fits all approach does not work.

The first step is to ensure that you have a comfortable and relaxing sleep environment. Eliminate distractions and anything that may be making it more difficult to sleep at night. Buying a new mattress can be the first step to getting more quality, rested sleep. Adding soft, warm lights may also help create an ideal sleep setting. Finally, you may also want to consider creating a relaxing bedtime routine to get your brain in the right frame of mind.

The most important thing you can do for your sleep health is to be sure that you aren’t suffering from any sleep-related health conditions. Sleep disorders like sleep apnea and insomnia are serious disorders that should be diagnosed and treated by a physician. If you think you have a sleep-related health disorder, make an appointment with your doctor to discuss your concerns.