How to Sleep 8 Hours in 4 Hours? You Can’t, Do This Instead

You can’t sleep 8 hours in 4 hours, but you can improve your sleep hygiene to fall asleep faster and wake up less often, so you spend less time awake in bed.
Published
2023-11-29
12 MINS
Written by
Jeff Kahn, M.S., Rise Science Co-Founder
Reviewed by
Chester Wu, MD, Rise Science Medical Reviewer
Our Editorial Standards
We bring sleep research out of the lab and into your life. Every post begins with peer-reviewed studies — not third-party sources — to make sure we only share advice that can be defended to a room full of sleep scientists.
Learn more
Updated Regularly
We regularly update our articles to explain the latest research and shifts in scientific consensus in a simple and actionable way.

How to Sleep 8 Hours in 4 Hours? 

  • It’s not possible to sleep eight hours in four hours. 
  • If you need more than four hours of sleep (as almost all of us do), you can’t hack your way into getting more sleep in less time. 
  • You can make your sleep more efficient and more restorative, though. The RISE app walks you through 20+ sleep hygiene habits to help you fall asleep faster and wake up less often, so you don’t need to spend too much extra time in bed to get the sleep you need.

We’d all like a few extra hours in our day, but we know getting a full night’s sleep is important. That’s where sleeping eight hours in four hours comes in. 

But, before you get your hopes up, it’s not possible to hack sleep like this. You can make your sleep more efficient, though. 

Below, we cover why you can’t sleep eight hours in four hours and how the RISE app can help you get enough sleep without too much extra time awake in bed.

A Sleep Doctor's Advice

A Sleep Doctor's Advice

“You can’t get eight hours of sleep in four hours, or any number of hours of sleep you yourself need in less time. That’s because there’s an amount of sleep each of us need to feel and perform at our best, and unfortunately, there’s no shortcut for this. You can make your sleep more efficient with good sleep hygiene, though.”

Rise Science sleep advisor and medical reviewer Dr. Chester Wu

How to Sleep 8 Hours in 4 Hours?

You can’t get eight hours of sleep in four hours, but you can spend less time in bed getting the sleep you need. 

You can do this through good sleep hygiene. With good sleep hygiene, you’ll fall asleep faster and wake up less often in the night, cutting down on your time awake in bed to get more of what sleep scientists call consolidated sleep.

Here’s what to do: 

  • Keep a regular sleep schedule 
  • Get out in sunlight first thing each morning 
  • Put on blue-light blocking glasses or avoid screen time about 90 minutes before bed 
  • Cut yourself off from caffeine, alcohol, large meals, and vigorous exercise too close to bedtime 
  • Do a relaxing bedtime routine, like reading or deep breathing  
  • Make your sleep environment cool, dark, and quiet 

Sleep hygiene is a sleep hack that’s backed by science. To make it even more effective, RISE tells you when to do 20+ sleep hygiene habits at the best time for your circadian rhythm, or body clock. 

Getting enough sleep for you at the right times for your circadian rhythm boosts your energy, focus, and health. And consolidated sleep is more healthy and restful than broken sleep.

“I never imagined that what you do throughout the day has such a profound impact on your sleep quality AND the energy dip in the afternoon. I now sleep better than ever and feel so much more productive throughout the day. Thank you RISE!” Read the review

We’ve covered the best time to sleep and wake up here.

RISE app screenshot showing sleep hygiene habit reminders
The RISE app can send reminders for when to do 20+ sleep hygiene habits.

RISE users on iOS 1.202 and above can set up their 20+ in-app habit notifications here

{{ cta }}

For Those Who Can’t Get More Than 4 Hours of Sleep

If you can’t get enough sleep right now — maybe you’re a new parent or struggling night shift worker — there are a few things you can do to make the most of the sleep you do get and keep your energy levels as high as possible. 

First, focus on sleep hygiene. This’ll make your sleep more efficient, so you get the most out of your time in bed.

Second, try to keep a regular sleep schedule (or as regular as you can). This will help to keep your circadian rhythm in check. This is protective for your health and leads to more consolidated sleep and higher energy. 

Third, try to keep your sleep debt as low as possible. 

Sleep debt is the amount of sleep you owe your body. When you get less sleep than you need, you start building up sleep debt. We measure it over 14 nights, so one night of four hours sleep isn’t the end of the world. But you’ll want to look for ways to pay back sleep debt, especially if you’re regularly missing out on sleep. 

Lowering your sleep debt can boost your energy, performance, and physical and mental health. 

You can pay back sleep debt by: 

  • Taking short afternoon naps (check RISE for the best time to nap) 
  • Heading to bed a little earlier  
  • Sleeping in a little later 
  • Improving your sleep hygiene (so you spend less time awake in bed) 

RISE can work out how much sleep debt you have each day. 

And fourth, if possible, schedule your day to match your natural peaks and dips in energy levels. These peaks and dips happen as part of your circadian rhythm — but they’ll be lower when you’ve little sleep. You’ll probably have a peak in energy mid morning, a dip in the afternoon, and a peak again late afternoon or early evening (if you’re a night owl, you’ll have your peaks a little later, and if you’re an early bird, a little earlier).

RISE can predict the timing of your circadian rhythm each day, so you can schedule your day to match when you’ll have the most energy and be at your most productive, despite not getting enough sleep. 

Learn more about how to function on no sleep to get you through the day after a four-hour night of shut-eye.

RISE app screenshot showing how much sleep debt you have
The RISE app tells you how much sleep debt you have.

RISE users on iOS 1.202 and above can view their sleep debt here.

{{ cta-mini }}

For Students 

Cramming for exams or juggling school with work and social commitments? Getting eight hours of sleep in four hours isn't the answer. Younger people tend to need more sleep, so getting four hours may be even more detrimental to your overall health and wellness.

Plus, the extra hours in your day probably won’t help you do better at school — they may even do the opposite. 

Research shows getting four or six hours of sleep a night for two weeks has the same effect on cognition as pulling two all-nighters. And a 2023 study found sleep duration can predict GPA — every hour of lost sleep was linked to a 0.07 reduction in end-of-term GPA.

Heads-up: Students get 50% off RISE. And we partner with high schools, colleges, and universities to bring RISE to students for free. Get in touch on social media or ask your school’s health administration to contact us to see if this is something your school can offer.

Is it Possible to Sleep 8 Hours in 4 Hours? 

We hate to break it to you, but it’s not possible to sleep eight hours in four hours. 

We all need a different amount of sleep and if that amount is more than four hours, four hours of sleep won’t be enough. There’s no way to hack sleep. 

Some lucky people have what’s known as short sleep syndrome. They only need about four to six hours of sleep a night — which research suggests is due to a gene mutation. But the vast majority of us need much more sleep than this. 

When we looked at how much sleep 1.95 million RISE users aged 24 and older need, we found it ranged from five hours to 11 hours 30 minutes, and 48% need eight hours or more. 

The RISE app can tell you how much sleep you need.
How much sleep RISE users need.

Heads-up: You can use RISE to find out your sleep need, the genetically determined amount of sleep you need a night. 

You can learn how much sleep you need here.

RISE users on iOS 1.202 and above can view their sleep need here

There are a few myths out there that make people think it’s possible to hack sleep. 

All Sleep Stages Are Important 

It’s easy to think deep sleep is the only important sleep stage, but every sleep stage is needed for maximum energy and recovery.

We spent more time in deep sleep in the first half of the night and more time in rapid-eye-movement sleep (REM sleep) in the second half. So cutting your sleep short after only four hours disproportionately affects REM. 

Research shows you spend less time in light sleep and REM when you sleep for four hours, but get the same amount of deep sleep as an eight-hour night. 

This doesn’t mean you’re sleeping eight hours in four hours, however! 

It means you’re missing out on vital REM, which is needed for creativity, regulating emotions, and consolidating memories.

When you get more sleep, you may experience REM rebound, getting more REM to make up for what you’ve missed out on. This can come at the expense of other stages of sleep. It’s unclear what the long-term effects of getting four hours of sleep or messing with your sleep stages would be. 

You Can’t Time Your Sleep to Match Your Sleep Cycles

You might have heard you should wake up at the end of a sleep cycle to feel your best. But you can’t use sleep cycles to hack sleep. 

Research is mixed on whether you’ll feel less groggy waking up in deep sleep compared to other sleep stages.

And sleep cycles look different for everyone and can change for you from night to night, and even throughout the course of one night. Plus, wearable devices that track sleep stages aren’t fully accurate. 

So it’s practically impossible to time your alarm clock to match your sleep cycles and get less sleep this way. 

You Need Good Sleep Quality and Sleep Quantity  

Another popular myth is that sleep quality is more important than sleep quantity. But that’s not true. Four hours of sleep won’t be enough, even if they’re good quality hours. Your brain simply won’t have the time to move through all the sleep cycles it needs.

What’s more, there’s no agreed-upon definition for sleep quality

The quality of your sleep matters, but so does the quantity. You need enough good quality sleep for you for the best energy, productivity, and health. 

We asked Dr. Jamie Zeitzer, co-director of the Center for Sleep and Circadian Sciences at Stanford University and one of our sleep advisors, whether you can sleep eight hours in four hours. Here’s what he had to say: 

“You can't. The first several hours of sleep are the most efficient in terms of dissipating sleep pressure, but the remainder are definitely needed to be at full alertness and performance.” 

Heads-up: Sleep pressure is the urge to sleep. It builds over the course of the day and helps us fall asleep at night. 

Learn more about why four hours sleep isn’t enough here. 

Is Getting 8 Hours Sleep in 4 Hours Healthy? 

Getting eight hours of sleep in four hours isn’t healthy. As it’s not possible to get more sleep in less time, four hours of sleep is just four hours of sleep. And as most of us need more sleep, you’re probably sleep deprived, which isn’t healthy. 

What Are the Side Effects of Not Getting Enough Sleep? 

Sleep is essential for energy, performance, and mental and physical health. The negative side effects of not getting enough sleep include:

In the short term:

In the long term:

  • Diabetes 
  • High blood pressure
  • Weight gain and obesity 
  • Cardiovascular disease 
  • Anxiety
  • Depression 
  • Chronic health conditions (2022 research found sleeping for five hours or less a night at ages 50, 60, and 70 ups the odds of having two or more chronic diseases like cancer and heart disease)
  • Early death

Learn how to know if you’re getting enough sleep here. 

{{ cta-mini }}

Can I Survive on 4 Hours of Sleep?

You may be able to survive on four hours of sleep, but your energy and productivity will take a huge hit. Your natural peaks in energy that come as part of your circadian rhythm — times when you’d usually be at your most productive — will be dampened by the lack of sleep. And in the long run, you’ll be upping your odds of serious health problems. 

You may subjectively feel fine on four hours of sleep for many reasons, including that your body is making more cortisol and adrenaline, which makes you feel alert. But high cortisol levels can lead to sleep loss, weight gain, and brain fog. 

And even if you feel fine, you may be performing poorly without even knowing it. Research shows people don’t notice the objectively measurable declines in mental performance that come with sleep loss.  

The accessibility and widespread use of caffeine and alcohol can also create a deceptive cycle where caffeine's alertness-boosting effects during the day mask the sedative impact of alcohol at night, leading to the false perception you’ve gotten enough quality sleep. This cycle, highlighted in a 2023 study of financial traders, shows how these substances can obscure their respective negative impacts on sleep quality and quantity, potentially leading to chronic poor sleep and its associated health and well-being consequences over time, without many of us even realizing it.

We dive deeper into why you might feel energized on less sleep here.

Is it Better to Sleep 4 Hours Twice or 8 Hours Once? 

It’s better to sleep eight hours once — or get however much sleep you need in one go — compared to breaking it up into chunks. 

Biphasic sleep, splitting your sleep into two chunks, can lead to sleep deprivation, missing out on vital sleep stages, and being out of sync with your circadian rhythm. Experts agree that monophasic sleep, getting the sleep your body needs in one go, is better for your health and well-being. 

Fragmented sleep is less restorative than consolidated sleep and can lead to daytime drowsiness and impaired performance. And one study found sleep interruptions can impact your mood more than getting the same amount of sleep in a shorter amount of time. 

Lead author of the study Patrick Finan, Ph.D. of Johns Hopkins University School of Medicine said, 

"When your sleep is disrupted throughout the night, you don't have the opportunity to progress through the sleep stages to get the amount of slow-wave sleep that is key to the feeling of restoration.”

Heads-up: You may know slow-wave sleep as deep sleep.  

More research is needed to find out the health consequences of biphasic sleep.

There’s limited research on polyphasic sleep, when you sleep in small chunks and for less time overall, but it leads to sleep deprivation and probably all the negative impacts we mentioned above. 

Make the Most of Your Time in Bed  

You can’t get eight hours of sleep in four hours — or enough sleep in fewer hours than you need. 

But you can make your sleep more efficient. Improve your sleep hygiene to fall asleep more quickly and wake up less often, so you don’t need much extra time in bed to get a good night’s sleep.

The RISE app can tell you when to do 20+ sleep habits at the right time for your circadian rhythm each day. 

Sleep hygiene is a sleep hack that works fast — 80% of RISE users get better sleep within five days. 

Try 7 days free

The power behind your next best day

RISE makes it easy to improve your sleep and daily energy to reach your potential

App store icon

Sleep Hygiene

View all
Popup Trigger
Try 7 days free

The power behind your next best day

RISE makes it easy to improve your sleep and daily energy to reach your potential

RISE app iconApp store icon