Most of us today are monophasic sleepers. That means we sleep for just one segment each day, typically during the nighttime hours. But this is a relatively modern sleep pattern. 

From as early as the stone age and up to the 17th century, people typically slept in multiple separate segments. They would wake up in the middle of the night, have an interlude for an hour or two, then drift back to sleep till morning. 

This type of sleep involving two sleep segments is called biphasic sleep. If you sleep for more than two segments, it is called polyphasic sleep. 

Brief History of Biphasic and Polyphasic Sleep?

Sleeping for a single continuous period each night seems pretty normal. Having more than one sleeping period sounds downright crazy and weird. Personally, I know if I tried to wake up in the middle of the night for a break, I’d never go back to sleep.  

But sleeping for multiple segments was standard for most of human society. Many societies slept in two segments at night. This type of sleep pattern went on up until around the 1600s. 

As industrialization picked up, people started shifting to the monophasic sleep pattern we are so familiar with today. This likely happened because most people could no longer afford to wake up during the night (since they had to wake up early) or even nap during the day. So they had to squeeze in as much sleep as they could in a single segment.  

Examples of Biphasic and Polyphasic Sleep 

While monophasic sleep is the order of the day, or rather night, there are still people who practice biphasic and polyphasic sleep. Some just naturally sleep in multiple segments, others are forced to do so by their work schedules and for others it can be as a result of a sleep disorder. 

You may also find yourself sleeping in segments because of jet lag or after you have a newborn in the house. 

A simple example of biphasic sleep that almost all of us have done at one time or another is sleeping at night and then napping during the day. It’s usually not deliberate. For some reason, you don't get enough sleep at night so you have to take a power nap around lunchtime to drive away the drowsiness. 

But you can also do it deliberately. For instance, you can decide to reduce your sleeping time to around 6 or 7 hours at night and then make it up with a 20-30 minute nap in the middle of the day. Or maybe sleep for 5 hours at night and have a longer 1-2 hour nap during the day. 

People who live in warm climates often have biphasic sleep, where they take a siesta in the afternoon when it’s too hot to work. 

Winston Churchil is one of the best known biphasic sleepers. He would combine a 5 hour sleep time with a 2 hour nap in the afternoon.  

You can also opt for a polyphasic sleep pattern, where you take more than two naps during the day and sleep for just a few hours at night. 

But there are other kinds of polyphasic sleep patterns. 

• Uberman — this is one of the more extreme ones out there. You take 30 minute naps every four hours for a total sleep time of 3 hours. 
• Everyman — you sleep for three hours at night then take three naps during the day, each 20 minutes long for a total sleep time of four hours. 
• Triphasic — this one is not as extreme but it can still leave you sleep deprived. You sleep early in the evening then wake up after a while. You catch some more sleep just before dawn and throw in a nap during the day.   

Pros and Cons of Biphasic and Polyphasic Sleep 

There’s very little research on biphasic and polyphasic sleep patterns, and especially their long term effects on health. But based on what we know so far, there’s a reason why a monophasic sleep pattern is the most popular. Biphasic and polyphasic sleep cycles have significant risks and drawbacks. 

The main advantage of having multiple sleeping segments is flexibility. You can work and sleep whenever you want. So if you are a night owl, you can sleep late and have a long nap in the afternoon. 

Polyphasic sleep grants you even more flexibility. You can work just as much during the night as you do during the day. 

Some people practicing polyphasic sleep claim to be more productive, have better memory and learning, and enjoy more lucid dreaming. But these are just anecdotal reports; there is no hard evidence that polyphasic and biphasic sleep has any major benefits over monophasic sleep. 

Risks and Drawbacks of Biphasic and Polyphasic Sleep Patterns

Here are the main downsides of multi-segmented sleeping patterns. 

• You are highly likely to end up sleep deprived. Many polyphasic sleep patterns are especially extreme with the total sleep time often adding up to less than five hours. Sleep deprivation has serious effects on your health, increases risk of diseases and could even reduce your longevity. 
• While segmented sleep affords you lots of flexibility, this flexibility is not very useful if you have to work traditional hours. I bet your boss won’t be happy if you are taking a 30 minute nap three times a day. 
• When you have an irregular sleep pattern, you are going against your body’s natural circadian clock. This could affect your health, cause drowsiness and reduce productivity. 
• Many people attempt segmented sleep to try and squeeze in more work into the 24-hour clock. But it often turns out the opposite. Because you are not getting enough sleep and at the right time, you are more likely to be less productive. You may also experience reduced focus and reaction time, which can be dangerous for jobs like driving. 

So is it worth it to try and divvy up your sleep time into multiple segments? Probably not. The risks are simply too great and there’s no evidence of any major upsides. 

What we know is that getting 7-9 hours of high quality and continuous sleep each night is the best way to sleep in our modern society. A good night’s sleep will boost your memory, productivity, learning, moods and overall health.    

There are plenty of productivity hacks worth considering, but biphasic/polyphasic sleep is one you should skip. 

That’s not to say you should never nap during the day. On days when you feel tired and drowsy, napping during the day can do wonders for your productivity and energy levels. 

But deliberately under-sleeping at night so that you can nap during the day is where things dicey. There’s no strong research backing this style of sleep. So take a power nap when necessary, but otherwise try to get a full night’s sleep.  

Famous people in history may have had weird sleeping patterns, but we don't know that their sleeping style is what made them successful. We also don't know what negative effects it had on them. 

Segmented Sleep Could Be a Sign of Sleep Disorder 

One last thing before I sign off. If you find yourself needing to sleep for more than one segment each day (e.g. you have to take a nap during the day), it could be a sign there’s something wrong with your sleep. 

Sleep deprivation is the most common culprit. Try to sleep for 7-9 hours each night, and you’ll find you won’t need to top it up with a nap. Have a regular sleep routine where you go to bed by 10 or 11pm to ensure you get adequate sleep. 

You may also be suffering from a sleep disorder like insomnia, restless leg syndrome or sleep apnea. With some of these disorders, you could be in bed for 8 hours but still get sleepy during the day. Consider talking to a doctor or sleep specialist for advice and possible treatment.