What is Biphasic Sleep & What are its Benefits?

Biphasic sleep is popular in several cultures. Often people who take short naps during the day or enjoy siestas are said to follow biphasic sleep schedules. While some people follow biphasic sleep as a routine practice some may follow it to increase their productivity.¹

While many people find biphasic sleep beneficial while some may not find it useful. What is biphasic sleep? Does it have any benefits? How different is biphasic sleep from sleeping at a stretch at night (monophasic sleep) or sleeping in smaller segments or phases (polyphasic sleep)?

Many people follow a biphasic sleep pattern, which is different from monophasic sleep. Taking a long sleep at night is monophasic sleep, as you sleep in one phase. But in biphasic sleep, you sleep in two phases for 24 hours. In this there are two segments of phases of sleep, hence the name biphasic sleep.

People may follow biphasic sleep schedules in different ways.

Some have a long sleeping segment at night and a short segment during the day, mostly in the afternoon. This could be about six to seven hours of sleep at night and a 30-minute nap in the afternoon.

Some follow a sleeping segment of about five hours at night and one to one and a half hours of sleep in the afternoon.

Some may split their night’s sleep into two segments, a few hours in the earlier part of the night and the remaining hours in the later part of the night, just before dawn.

Biphasic sleep has its pros and cons. Most of the time biphasic sleep is practiced by sleeping during the night and for some time during the day. Thus, taking the pattern of napping during the day is largely a part of the biphasic sleep schedule. Several studies have supported napping during the day and the pattern of splitting sleep between the night and a daytime nap for better health and performance.²

Here are some benefits of biphasic sleep:

1. Compensation for Sleep Deprivation

   Biphasic sleep can be particularly useful for people who are unable to sleep for the whole night. This could be due to disturbances during sleep, work schedules where you need to sit till late at night or wake up early in the morning, shift workers, and people traveling. Students too may experience this problem of inadequate sleep and have to find ways to make up for their sleep. The best way to compensate for such sleep deprivation at night is to split your sleep into most hours at night and for short periods during the day.

   Following a biphasic sleep schedule can help in recovering from the lost sleep and splitting sleep into two parts or napping can have benefits on your performance too.

2. Better Memory

   Taking short naps during the day can help boost your memory. Hence, following a biphasic sleep schedule with a long night’s sleep and a short nap during the day can be beneficial.

   A 2021 study confirmed that daytime naps are linked with enhanced memory. Also, there were no negative effects of splitting the sleep schedule on the morning performance of the study participants. The study suggested that naps can be incorporated into a daily sleep routine that provides adequate sleep and also helps in better learning.²

   Scientists found that people who slept for 30 to 90 minutes during the day showed better memory and cognition than those who did not sleep during the day or those who slept for more than 90 minutes during the day.³

3. Better Healing

   Many people complain of sleep disturbance during the night. Taking short naps during the day may be helpful in such cases, as the recommended number of sleep hours can be maintained in addition to promoting better healing.

   A 2021 study reported that a diurnal nap can be beneficial to enhance the recovery process and counter the negative impact of sleep deprivation on physical and cognitive performance. This was studied to optimize the physical performance of athletes who had experienced chronic sleep insufficiency. The study concluded that a nap of 90-minute duration can be beneficial to promote better healing.⁴ Thus, sleep can be split into a 90-minute duration during the day and the remaining hours during the night for better healing.

4. Improved Performance

   Lack of adequate sleep is an increasing concern for many. This can not only affect alertness, and performance but also overall health and increase the risk of metabolic disorders. Adolescents are often exposed to sleep restrictions, which can harm their health.

   A 2019 study was conducted to study the effects of split sleep on adolescents, as even though they take compensatory naps they fall short of adequate sleep and hence are at risk of health problems. During the study, the adolescents experienced six and half hours of sleep per day. It was observed that in the group practicing biphasic sleep schedule or sleeping at night plus napping during the day, their working memory, processing speed, alertness, and mood were less impaired as compared to the group practicing continuous night sleep or monophasic sleep schedule.⁵

5. Better Health

   Napping during the day for a short while is found to be effective in improving overall health.

   Experts believe that short naps during the day are associated with a lower incidence of cardiovascular disorders. These shorter naps offering cardiovascular benefits are mostly 30 minutes in duration, which is one of the best benefits of biphasic sleep.⁴

   Some studies have also reported the beneficial effects of napping to relieve stress and improve immunity. When participants could overcome their nighttime sleep deprivation through daytime sleeping, the levels of chemicals linked with stress and immunity were found to be high. Thus, following a biphasic sleep pattern can give you these health benefits and improve your overall well-being.

You need to know a few important points before planning to practice biphasic sleep or if you are already napping in the afternoon.

Sleep Deprivation – Even if you practice a biphasic sleep schedule, it is necessary to complete the recommended hours of sleep in 24 hours, to avoid sleep deprivation. So, if you sleep for an hour in the afternoon, it is necessary to cover the remaining seven to eight hours of sleep, based on individual requirements.

In a 2019 study, of restricted sleep hours, it was also noted that the group practicing a split sleep schedule had higher levels of blood glucose when tested on a glucose tolerance test. This may be due to the sleep restriction of six and half hours per day, which shows that it may be difficult to sustain restricted sleep hours. Also, a sleep-restricted schedule, whether in the form of a monophasic or biphasic sleep pattern often comes with negative health consequences. Hence, aiming at taking about eight to ten hours of nocturnal sleep is very important.⁵

Napping Hours – Some people may not be able to sleep at night if they sleep in the afternoon. In such cases, you need to adjust your time and the duration of hours of daytime sleep such that your nighttime sleep is not affected. People with insomnia can limit their daytime napping hours. Also, longer naps during the day are associated with a significantly elevated risk of cardiovascular diseases and all-cause mortality.⁶

Experts believe that sleeping for long hours during the day, which can mean poor sleep quality at night can lead to cognitive problems. Hence, restricting the time of daytime sleeping is important while practicing a biphasic sleep routine.

This means that if you follow a biphasic sleep pattern, it is best to take a long sleep segment at night and a short sleep segment during the afternoon hours such that you maintain the recommended hours of sleep.

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