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Is 5 Hours of Sleep Enough? It’s Highly Unlikely

Most of the time, 5 hours of sleep isn’t enough. Use RISE to find out how much sleep your body really needs.
Published
2021-06-02
Updated
2024-01-29
14 MINS
Written by
Jeff Kahn, M.S., Rise Science Co-Founder
Reviewed by
Jamie Zeitzer, PhD, Rise Science Scientific 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.
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Updated Regularly
We regularly update our articles to explain the latest research and shifts in scientific consensus in a simple and actionable way.
Woman sleeping at desk in front of laptop after only five hours of sleep.

Is 5 Hours of Sleep Enough? 

  • Five hours of sleep most likely isn’t enough to feel and function your best. 
  • Most of us need seven and a half to nine hours of sleep, and some of us may need even more. 
  • To find out exactly how much sleep you need, use the RISE app. RISE can also guide you through good sleep habits to help you get enough shut-eye each night.

Whether you’re getting five hours of sleep because of a busy work schedule or a teething toddler, you’re — most likely — not getting enough sleep. 

You might feel fine after five hours of shut-eye, but really, your energy levels, health, and mental and physical performance will all take a hit. The good news? You can find out how much sleep you really need and follow some science-back tips to help get it. 

Below, we’ll dive into whether five hours of sleep is enough (spoiler: it’s not!) and what happens when you don’t get enough sleep. Plus, we’ll share how the RISE app can calculate how much sleep you really need at night and make getting enough shut-eye easier.

Advice from a sleep doctor:

For a sleep doctor’s opinion, we asked our medical reviewer, Dr. Chester Wu, who’s double board certified in psychiatry and sleep medicine.

“For most of the population, five hours of sleep isn’t enough. Most people need around eight hours. If you’re only getting five hours right now, try going to bed 15 minutes to 30 minutes earlier tonight and getting more sleep over the course of a couple of weeks. You might be surprised at how good you feel!”

Is 5 Hours of Sleep Enough?

The TL;DR: five hours of sleep isn’t enough for the vast majority of us. 

We all have an individual sleep need. This is the amount of sleep we need a night. It’s determined by genetics — just like height and eye color — and it’s set by early adulthood.

When we looked at the sleep needs of 1.95 million RISE users aged 24 and older, we found the median sleep need was eight hours. Almost half of our users need eight hours or more sleep a night, and some need a whopping 11 hours 30 minutes — a far cry from five hours.

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

It’s not just our data that points to most of us needing more than five hours of shut-eye. One small sleep extension study estimated the sleep needs of adults aged 20 to 26 and found the mean sleep need was eight hours 25 minutes. Sleep needs ranged from seven hours 17 minutes to nine hours 16 minutes. 

While there are a few lucky people out there who can survive on only five hours of sleep, these short sleepers are very — very — few and far between. 

Dr. Thomas Roth puts it in perspective in Matthew Walker’s book Why We Sleep, “The number of people who can survive on 5 hours of sleep or less without any impairment, expressed as a percent of the population, and rounded to a whole number, is zero.”

Walker elaborates, “It is far, far more likely that you will be struck by lightning (the lifetime odds being 1 in 12,000) than being truly capable of surviving on insufficient sleep thanks to a rare gene.” 

And even if you have one of these rare genes, you’re not guaranteed to be able to get by on a short amount of sleep. Learn more about so-called short sleep syndrome here.

RISE app screenshot showing your sleep profile
The RISE app can work out how much sleep you need.

The National Sleep Foundation recommends healthy individuals with normal sleep get:

  • Newborns: 14 to 17 hours 
  • Infants: 12 to 15 hours 
  • Toddlers: 11 to 14 hours 
  • Preschoolers: 10 to 13 hours 
  • School-aged children: 9 to 11 hours 
  • Teenagers: 8 to 10 hours 
  • Adults: 7 to 9 hours 
  • Older adults: 7 to 8 hours 

But as you can see, there’s a wide range in the recommendations for each age group. And as one paper states, “there is no “magic number” for the ideal duration of sleep.” 

These guidelines are exactly that: guidelines. They're based on surveys that look at how much sleep people get — not what they actually need. And beyond that, guidelines like these are often based on inaccurate self-reported data and don’t take into account individual sleep needs.

What’s more, these guidelines can be misleading. Older adults may not actually need less sleep than younger adults. Sleep is just harder to come by, so data can show older adults get (and therefore it’s assumed need) less sleep. 

For example, when we looked at RISE user data, we found the median sleep need for those over 60 was 8.3 hours. And the median sleep need for those aged 24 to 59 was 8.4 hours — only a few minutes difference. 

Instead of relying on vague guidelines, work out your individual sleep need. 

You can do this by:

Waking Up Without an Alarm for a Week or Two

Keep track of how much sleep you get when you don’t force yourself up with an alarm. 

This method can be inaccurate, however. Who can know down to the minute when they fell asleep exactly and how long they were awake for during the night? 

Studies show we tend to inflate our estimated sleep duration. And as five hours in bed rarely equals five hours of sleep, we may be getting much less sleep than we think. 

Plus, if you suddenly start getting nine hours of sleep without an alarm, it’s hard to tell if you’re getting nine hours because that’s your sleep need, or because your body’s taking the opportunity to catch up on lost sleep as you’ve been getting five hours recently.

You may also temporarily need more sleep when you’re ill or recovering from intense exercise or a muscle injury.

Using the RISE App 

RISE works as a personal sleep calculator to tell you exactly how much sleep you need in hours and minutes. 

The app uses a year’s worth of phone use data and proprietary sleep-science-based models to calculate your sleep need.  

You can learn more about how much sleep you need here.

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

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What Happens if You Only Get 5 Hours of Sleep?

RISE app screenshot showing how much sleep debt you need
The RISE app can work out how much sleep debt you have.

Getting five hours of sleep (or six, or seven, or fewer hours than your sleep need) has negative effects the next day and health problems in the long run.

In the short term: 

  • More daytime sleepiness 
  • Increased irritability 
  • Poorer decision-making skills 
  • Reduced attention span and focus 
  • Digestive issues 
  • Weakened immune system (a 2023 study found there’s a 27% increased risk of infection in those who get less than six hours of sleep)

In the long term: 

  • Lowered mental performance: A 2018 sleep study found cognitive performance is impaired if you regularly get less than seven to eight hours of sleep. And regularly sleeping for only four hours a night had the equivalent cognitive impairment as aging eight years.
  • Increased risk of having multiple health conditions: A 2022 study found sleeping for five hours or less a night at ages 50, 60, and 70 was associated with a high risk of multimorbidity, or having two or more chronic diseases. 
  • Increased risk of weight gain: And weight gain can lead to obesity and all the health issues that’s linked to.
  • Increased risk of cardiovascular diseases and heart problems: Such as high blood pressure, stroke, heart disease, and heart attacks.
  • Increased risk of mental health conditions: Such as anxiety and depression.

Why You Feel Fine on Five Hours of Sleep 

If you feel fine after five hours of sleep, that doesn’t necessarily mean five hours of sleep is enough. One study gave participants the opportunity to sleep for up to 12 hours. Even though participants thought they were getting enough sleep beforehand, when given the 12-hour opportunity, they slept for an average of three hours more than usual. So they may have been sleep deprived and didn’t even know it. 

Plus, research suggests we are largely unaware of the increasing declines in cognitive performance we get from sleep loss. 

And if you feel more alert on less sleep, you can blame a surge in the stress hormone cortisol for that (over time, high cortisol levels can lead to more sleep loss and health issues like weight gain and high blood pressure).

Even if we feel the effects of sleep deprivation, we may attribute them to other factors, like stress or health conditions, instead of the true culprit: not getting enough sleep.

We asked one of our sleep advisors, Dr. Jamie Zeitzer, who’s the co-director of the Center for Sleep and Circadian Sciences at Stanford University, for his opinion. 

“It’s easy to feel like five hours is enough sleep, but our bodies are very good at tricking us. You’ll produce more cortisol when sleep deprived, so you’ll feel alert, and you may not even notice your performance taking a hit.”

The Most Important Sleep Metric: Sleep Debt 

One key way to minimize these risks? Keep your sleep debt low. When you don’t get enough sleep, you build up sleep debt. This is the amount of sleep you owe your body. 

The higher your sleep debt, the worse you’re going to feel and function in the short term, and the worse your quality of life and overall health and well-being may be in the long run.

Heads-up: Sleep debt is one of the biggest factors determining how you feel each day. Sleep cycles, quality sleep measurements, and the amount of time spent in deep sleep and REM sleep are interesting. But if you want to have more energy, studies show sleep debt is the metric to focus on. 

Plus, it’s one of the only metrics you can control. The best way to get enough deep sleep and REM sleep, for example, is to get enough sleep overall. When you spend enough time sleeping, your brain can self-optimize and spend the right amount of time in each sleep phase. 

When you cut your sleep short, however, you may lose out on much more deep sleep and REM sleep than you think. That’s because we spend more time in deep sleep in the first half of the night and more time in REM sleep in the second half of the night. If you get up after only five hours of sleep, you’re not just losing out on three hours of sleep (if you need eight hours), you could be losing out on most of the REM you need. 

Not sure how much sleep debt you have? We work out your sleep debt based on the last 14 nights of sleep. Try keeping it below five hours to maximize your energy, health, and productivity. 

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

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Why Do I Only Sleep for 5 Hours?

Only getting five hours of sleep a night, even when you try for more? Here’s what could be to blame. 

1. Your Sleep Need is Five Hours 

There is a small chance your sleep need is five hours. If this is the case, you may find it hard to sleep for longer as your body simply doesn’t need the extra shut-eye. 

As we said above, though: this is very, very rare. 

Check RISE to see if your sleep need is five hours. 

2. You’ve Got Poor Sleep Hygiene 

Sleep hygiene is the set of daily behaviors that influence your sleep. If you’ve got poor sleep hygiene, you may struggle to fall asleep and wake up often throughout the night. It’ll therefore be much harder to get enough sleep each night. 

Poor sleep hygiene includes: 

  • Having a bedroom that’s too warm, noisy, or bright 
  • Not getting light exposure in the morning or daytime 
  • Getting too much light exposure close to bedtime 
  • Having caffeine, doing intense exercise, drinking alcohol, or eating large meals close to bedtime 
  • Not winding down and relaxing before bed (RISE users state the biggest barrier to a good night’s sleep is stress and anxiety)

3. You’re Out of Sync with Your Circadian Rhythm 

Your circadian rhythm is your internal body clock. It runs on a roughly 24-hour cycle and helps to control your sleep cycle.

If you’re out of sync with your circadian rhythm, you could find yourself waking up after only five hours of sleep. 

You might be out of sync if: 

  • You work night shifts
  • You have social jetlag — or you have different sleep patterns on your work days and days off. 
  • You’re living at odds with your chronotype — like when a night owl tries to go to bed early or an early bird tries to sleep in later 

RISE can predict your circadian rhythm each day and show you when your body naturally wants to go to sleep and wake up. You can then see if you’re working against your biology and this is causing you to sleep less than you’d like. 

RISE users on iOS 1.202 and above can click here to see their circadian rhythm on the Energy screen.

4. You’ve Got a Sleep Disorder or Medical Condition 

A sleep disorder or medical condition may be stopping you from getting enough sleep. 

These include: 

  • Insomnia 
  • Sleep apnea
  • Restless leg syndrome  
  • Anxiety 
  • Depression 
  • High blood pressure 
  • Diabetes 
  • Chronic pain 
  • Side effects from medications 

Speak to your healthcare provider if you think a sleep disorder or health condition is causing a lack of sleep.

Hormone changes may also be to blame for short sleep. You may find it harder to sleep for more than five hours when you’re on your period, pregnant, or going through menopause

How to Get Enough Sleep?

RISE app screenshot showing when to limit caffeine intake
The RISE app can tell you when to do 20+ sleep hygiene habits.

Now you know that five hours of sleep isn’t enough for most of us, it’s time to start getting more shut-eye. But that is often easier said than done. 

To help get more sleep, focus on your sleep hygiene. These behaviors have been scientifically proven to help you get a good night’s sleep. 

Here’s what to do: 

  • Get bright light first thing: Light in the morning resets your circadian rhythm for the day, which helps you feel alert and sleepy at the right times. Aim for at least 10 minutes of light as soon as possible after waking up, and 15 to 20 minutes if it's overcast or you’re getting light through a window. 
  • Avoid light close to bedtime: Light suppresses the sleep hormone melatonin. Dim the lights and put on blue-light blocking glasses about 90 minutes before bed (we recommend these).
  • Avoid caffeine, large meals, intense exercise, and alcohol too late in the day: You don’t need to give up these sleep disruptors, you just need to get the timing of them right. RISE can tell you when to avoid each one daily for better sleep.
  • Keep your bedroom dark, cool, and quiet: Aim for 65 to 68 degrees Fahrenheit, use blackout curtains, and wear earplugs or use a white noise generator and an eye mask. RISE has white noise sound recordings you can play from the app. RISE users on iOS 1.202 and above can click here to go right to their relaxation audio guide homepage and get started.
  • Keep a regular sleep schedule: Aim to go to bed and wake up at similar times each day, even on weekends. Make sure this sleep schedule gives you enough time to meet your sleep need each night. 
  • Avoid sleep aids: Sleep aids come with side effects and can cause sleep problems when you stop taking them.

To make it easier to stay on top of sleep hygiene, RISE can tell you when to do 20+ sleep habits each day and the ideal time to do each one to make them more effective.

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

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Is 4 Hours (or Less) Sleep Enough?

Four hours of sleep isn’t enough. And while we’ve got you, two hours or three hours of sleep isn’t enough, either. 

We all need a different amount of sleep, but your sleep need is most likely going to be much more than four hours.

What happens when you only get four hours? Everything from your energy levels to your mood to your mental and physical health will take a hit. 

You’ll have a higher risk of health conditions like type 2 diabetes and heart disease. And your mental performance will suffer, too. A 2018 study found a self-reported typical sleep duration of four hours had the equivalent drop in mental performance as aging eight years.

Heads-up: Taking naps to make up for only getting four hours of sleep at night? It may not be enough. While afternoon naps are a great way of paying down sleep debt and boosting your energy levels, sleep works best when it’s uninterrupted. That is, you want to ideally meet your entire sleep need at night. 

What’s more, even with a nap, you’re probably not meeting your full sleep need, so you’ll still get all the adverse effects of sleep deprivation.

Check RISE to see how much sleep you need a night. 

Learn more about why four hours is almost certainly not enough sleep for you here.

Get More Sleep to Be at Your Best  

With a growing to-do list, busy family lives, and endless errands to run, only sleeping for five hours sounds great. 

But, unfortunately, five hours of sleep isn’t enough for most of us. If you only get five hours, your energy levels, mood, and productivity will be lower in the short term, and you’ll have a greater risk of serious health conditions in the long term. 

How much sleep is enough? That number is different for each of us. 

Use the RISE app to find out your unique sleep need. Then, to help you meet this sleep need, follow RISE’s personalized reminders for 20+ sleep hygiene habits to help you fall faster and have fewer awakenings throughout the night. 

It doesn’t take long: 80% of RISE users get more sleep within five days!

FAQs

Is 5 hours of sleep OK?

For most of us, five hours of sleep is not OK. Most adults need about eight hours of sleep. And while some people need five hours, it’s extremely rare. For most of us, five hours of sleep can lead to chronic sleep deprivation, low energy, poor focus, and long-term health issues.

Is 5 hours of sleep better than none?

Five hours of sleep is better than none. But five hours of sleep isn’t enough sleep in the long term. Most of us need about eight hours of sleep, and only getting five hours can lead to low energy, poor focus, and long-term health issues.

How little sleep can you survive on?

You can survive on just a little sleep, but your energy, mood, focus, and mental and physical health will all suffer. We don’t know for sure how little sleep you can survive on. There aren’t many studies looking at sleep deprivation for longer than 72 hours as this is deemed unethical.

Is 5 hours of sleep enough once a week?

No, 5 hours of sleep isn't enough once a week. For optimum energy levels, good health, and maximum performance, you need to meet your individual sleep need each night — which is most likely more than five hours.

How to survive on 5 hours of sleep?

If you need to survive on 5 hours of sleep, try to live in sync with your circadian rhythm and get more sleep through naps, if possible, to minimize the effects of the sleep deprivation. Get bright light, drink coffee (not too close to bedtime), exercise, and take a cold shower to boost your energy levels.

I only sleep 4-5 hours a night

If you only sleep for 4-5 hours a night, you may have a sleep disorder like insomnia or sleep apnea. Poor sleep hygiene — like getting late-night bright light, eating large meals before bed, or drinking coffee too late in the day — may also keep you up past bedtime.

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Rise is the only app that unlocks the real-world benefits of better sleep.

Instead of just promising a better night, we use 100 years of sleep science to help you pay down sleep debt and take advantage of your circadian rhythm to be your best.

Over the past decade, we've helped professional athletes, startups, and Fortune 500s improve their sleep to measurably win more in the real-world scenarios that matter most.

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