Is 6 Hours of Sleep Enough? No, Here’s How Much You Need

Six hours of sleep isn’t enough for the vast majority of us. The RISE app can tell you how much sleep is enough for you.
Updated
2024-02-26
15 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.

Is 6 Hours of Sleep Enough? 

  • Six hours of sleep isn’t enough for the vast majority of us. 
  • Most of us need seven and a half to nine hours of sleep a night to feel and perform our best. 
  • The RISE app uses sleep science algorithms and your personal phone use behavior to work out how much sleep you need each night.

Getting six hours of sleep a night and feeling great the next day may sound like the dream. Think of all the extra time you’d have for work, for hobbies, or just for Netflix in the evening. But, unfortunately, six hours simply isn’t enough sleep for most people. 

It might not feel too far off the often recommended seven to nine hours of sleep, but even a small amount of sleep deprivation can have huge impacts on your energy, productivity, and health.  

Below, we’ll dive into whether six hours of sleep is enough, the impacts of only getting six hours of sleep, and how you can use the RISE app to find out how much sleep you need. 

Is 6 Hours of Sleep Enough?

Six hours of sleep isn’t enough for the vast majority of people. 

Your sleep need — or the genetically determined amount of sleep you need — is very likely more than six hours. In fact, it’s probably much closer to, or more than, eight hours. 

At RISE, we work out your sleep need using a year’s worth of phone use behavior and proprietary sleep-science-based models. 

When we looked at the sleep needs of 1.95 million RISE users aged 24 and older, the median sleep need was eight hours. Almost half (48%) need eight hours or more sleep a night, and some users even need 11 hours 30 minutes — that’s almost double six hours! 

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

Sleep studies also show most of us need more than six hours of sleep. One small sleep extension study worked out the sleep needs of adults aged 20 to 26. The mean sleep need was eight hours 25 minutes, and sleep needs ranged from seven hours 17 minutes to nine hours 16 minutes. 

There are a few lucky ones who have a sleep need of six hours. But it’s rare — really rare. 

Scientists at the University of California, San Francisco discovered that the NPSR1 gene mutation allows you to get by on about four to five and a half hours of sleep a night. The catch? The gene is found in fewer than one in 4 million people.  

What’s more, even if you have one of these genes, you’re not guaranteed to be able to get by on a short amount of sleep. 

We cover more on so-called short sleep syndrome and how to know if you have it here.

What does a sleep doctor have to say on the matter? We turned to one of our medical reviewers, Dr. Chester Wu, who runs his own sleep medicine practice.

“We’re often told to get between seven and nine hours of sleep a night, so six hours doesn’t sound too far off. But six hours of sleep simply isn’t enough for most people. Try getting a little more sleep over the next few weeks and seeing how you feel.”

What’s the Recommended Amount of Sleep?

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

According to the National Sleep Foundation, here’s how much sleep you should be getting depending on your age group: 

  • 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 
  • Young adults and adults: 7 to 9 hours 
  • Older adults: 7 to 8 hours 

While these recommendations are helpful starting points, you shouldn’t necessarily shoot for seven to nine hours and hope for the best. 

These guidelines are simply guidelines. They come from studies looking at how much sleep people get, not how much they need, they’re based on self-reported data (which is notoriously inaccurate), and they don’t take into account individual differences. 

In fact, older adults may not actually need less sleep at all. It’s just harder to come by. Data shows they get less sleep, so it’s assumed they need less. 

When we looked at our own sleep need data, we found the median sleep need for RISE users over 60 was 8.3 hours. The median sleep need for those aged 24 to 59 was 8.4 hours — only a few minutes longer.

Sleep is vital to everything important in life: energy, health, focus, mood. It’s not something you want to leave to guesswork and guidelines.  

So, how do you know how much sleep is enough for you personally? There are two ways to find out: 

Wake Up Without an Alarm Clock for a Week or Two

Ditch the alarm and note the times you naturally fall asleep and wake up. This can be tricky to get right, however, as it’s hard to accurately measure your sleep time. 

Studies show we tend to think we got more sleep than we actually did. And as six hours in bed rarely equals six hours of sleep, you may be getting a lot less shut-eye than you think. 

Plus, if you find you’re suddenly sleeping for nine hours, it’s hard to tell if that’s because your sleep need is nine hours or if your body’s catching up on the sleep it’s lost out on after several nights of six hours. 

And you may temporarily need more sleep because you’re ill, you’ve just done intense exercise, or because of a muscle injury.

Use the RISE App

Let algorithms do the hard work for you. 

RISE acts as a sleep calculator and works out your individual sleep need down to the minute, so you know exactly how much shut-eye is enough for you. 

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 Six Hours of Sleep?

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

Six hours of sleep doesn’t sound too bad, but it can be more harmful than you think. 

When you get less sleep than you need, you start building up sleep debt. Sleep debt is the amount of sleep you owe your body. 

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 — how bad sleep debt really is.

“In the short term, sleep debt can lead to sleepiness, poor mood, and lowered productivity. And in the long term, you’ll have an increased risk of heart disease, obesity, and type 2 diabetes — just to name a few. To make matters worse, it’s easy to attribute the short and long-term symptoms of sleep debt to other factors, so we never realize just how sleep deprived we are.”

Not getting enough sleep can lead to: 

The Science Behind Six Hours of Sleep 

Don’t believe six hours of sleep can have these effects? Here’s some science to back it up. 

One study looked at participants who got four, six, or eight hours of sleep a night for 14 nights. Another group had no sleep at all for three nights.

Those who got four or six hours of sleep saw their cognitive performance take a hit, and it got progressively worse the more sleep deprived they became.   

And while pulling all-nighters certainly tanks your performance, the results showed getting six hours or less sleep over the course of two weeks produced the same mental performance deficits as getting no sleep at all for two nights.

Even more worryingly, participants on six hours or less sleep per night were largely unaware of the negative effects on their mental performance. That is to say, we tend to get used to the effects of sleep deprivation and think we’re doing fine. 

Beyond mental performance, your physical health and well-being is at risk, too. One study found those who get six hours or less sleep a night are four times more likely to catch a cold than those who get seven hours.

Lead author of the study, UCSF sleep researcher Aric Prather, said short sleep was more important than any other factor when predicting the likelihood of catching a cold 

“It didn't matter how old people were, their stress levels, their race, education or income. It didn't matter if they were a smoker. With all those things taken into account, statistically sleep still carried the day,” said Prather. 

It’s not just a cold, either. A 2023 study found sleeping for six hours or less was associated with higher odds of having a medical condition, including diseases of the nervous system, musculoskeletal system, digestive system, and circulatory system. 

Is Six Hours of Sleep Enough for Me? 

Six hours of sleep is unlikely to be enough sleep for you. Six hours of sleep also has different impacts for certain groups.

For example: 

  • Six hours of sleep may not be enough for athletes: A 2019 study found sleep deprivation lowered athletes’ physical performance, including their reaction time, accuracy, vigor, strength, and endurance. On the flip side, getting more sleep can improve reaction times, sprint times, tennis serve accuracy, swim turns, kick stroke efficiency, and free throw and 3-point accuracy. 
  • Six hours of sleep may not be enough when pregnant: One study found those who slept for six hours or less a night had longer labors and were 4.5 times more likely to have cesarean deliveries. Pregnant and struggling to get enough shut-eye? We’ve covered how to sleep when pregnant here.
  • Six hours of sleep may not be enough for students: Research shows the more sleep students get, the higher their GPA. And one study found irregular sleep patterns are linked to poorer academic performance.
  • Six hours of sleep may not be enough to lose weight: Research shows people who regularly sleep for six hours or less tend to have a higher body mass index (BMI) and fat percentage. We’ve covered more on the link between sleep and weight loss here.
  • Six hours of sleep may not be enough for those who take naps as well: If you get six hours of sleep a night and then take a daytime nap, it’s not the same as getting a full night’s sleep. Sleep works best when it’s uninterrupted, so to feel your best and keep health conditions at bay, you’d ideally want to meet your sleep need at night, instead of relying on naps. Even with six hours of sleep and a nap, you’re unlikely to meet your full sleep need.

Heads-up: Sleep debt is the most important sleep metric to focus on as it has the biggest impact on how you feel and function each day. But cutting your sleep short affects how long you spend in certain sleep stages — and not in an even amount. 

That’s because we spend 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 of the night. 

So, if you need eight hours of sleep and only get six, it’s easy to think you’re only missing out on two hours, or 25%, of your sleep need. But if you get up after only six hours, you may actually miss out on 60% to 90% of your REM, which is needed for emotional processing and memory consolidation.

Expert tip: The best way to get enough deep sleep and REM sleep is to meet your overall sleep need. When you get enough sleep, your brain can self-optimize and spend the right amount of time in every sleep stage. 

Want to see how much sleep you’ve been missing out on recently? RISE can work out how much sleep debt you’re carrying. 

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

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Why Do I Only Get 6 Hours of Sleep?

There are many reasons you might be only getting six hours of sleep, despite trying to get more. 

1. Your Sleep Need is 6 Hours

There’s a chance you’re a natural short sleeper and may only need six hours of sleep a night. This chance is small, however. 

Check RISE to see if you’re one of the lucky few with a sleep need of six hours. 

2. You’ve Got Poor Sleep Hygiene 

Sleep hygiene is the set of daily habits you can do to get a good night’s sleep. Get sleep hygiene right and you can fall asleep faster and wake up less often in the middle of the night.

Get it wrong, however, and you may struggle to get enough sleep, even when you try to sleep for more than six hours. 

Poor sleep hygiene includes: 

  • Not getting enough light exposure in the morning or daytime 
  • Getting too much light exposure in the evenings 
  • Eating large meals, doing intense exercise, drinking alcohol, or drinking coffee too close to bedtime 
  • Not having a regular sleep schedule 
  • Not winding down before bed (RISE users say their biggest barrier to a good night’s sleep is stress and anxiety keeping or waking them up) 

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

RISE app screenshot showing your energy schedule
The RISE app can predict your circadian rhythm each day.

Your circadian rhythm is your roughly 24-hour internal biological clock. It dictates when you feel alert and when you feel sleepy. 

If you’re not in sync with your circadian rhythm, you could find yourself struggling to get to sleep at night or waking up early, even though you’ve only had six hours of shut-eye.

You might be out of sync with your circadian rhythm if: 

  • You work night shifts
  • You’ve got social jetlag — or an irregular sleep schedule 
  • You’re at odds with your chronotype — like a night owl trying to go to sleep early  

How do you know if you’re in sync or not? RISE can predict your circadian rhythm each day and show you a visualization of it in the app. You can then see when your body naturally wants to wake up, wind down for sleep, and go to bed — and you can sync up with these times. 

RISE can also tell you your biological bedtime, the roughly one-hour window of time when your body’s rate of melatonin production (the sleep hormone) is rising its fastest. We call this your Melatonin Window. Try heading to bed within this time to have an easier time falling asleep. 

RISE users on iOS 1.202 and above can click here to see their circadian rhythm and here to set up a reminder to check their Melatonin Window.

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

Sometimes, a sleep disorder or medical condition can cause sleep loss and stop you from getting more than six hours of sleep.  

These include: 

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

Your personality may even play a part in how many sleep problems you have. A 2023 study found you’re more likely to experience sleep disturbances if you have personality traits like neuroticism, impulsivity, and extraversion.  

5. Your Bedroom Isn’t Set Up for Sleep

Sometimes, something seemingly as simple as an uncomfortable mattress or snoring partner can cut your sleep duration short.

And other times, furry friends are to blame for a lack of sleep. A 2023 study found owning a dog was associated with higher odds of having trouble sleeping. 

Make sure your bedroom is cool, dark, and quiet to maximize your chances of getting enough sleep. 

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 daily.

Six hours of sleep isn’t enough for most of us, but how do you get more sleep? Improving your sleep hygiene is the answer. 

Here’s what to do: 

  • Get bright light first thing: This resets your circadian rhythm for the day and keeps your sleep cycle in check. Aim for at least 10 minutes of light as soon as possible after waking up, or 15 to 20 minutes if it's overcast or you’re getting light through a window. 
  • Avoid light close to bedtime: Evening light pushes back your circadian rhythm, so you struggle to fall asleep at bedtime. Dim the lights and put on blue-light blocking glasses about 90 minutes before bed to stop this from happening.
  • Avoid caffeine, large meals, intense exercise, and alcohol too late in the day: All four can contribute to insufficient sleep. RISE can tell you when to avoid each one daily.
  • Do a calming bedtime routine: This will help slow your body and mind down for sleep. Try reading, listening to music, or doing breathing exercises before bed.
  • 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.

RISE can guide you through all of these habits, and more, to keep your sleep hygiene on point. 

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

Get Enough Sleep for You 

Six hours of sleep sounds like almost a full night, but for the vast majority of us, six hours isn’t enough sleep. Most healthy adults need closer to or more than eight hours for maximum energy, top mental performance, and good health.  

Skip worrying about deep sleep, REM sleep, or quality sleep, and focus on getting enough sleep overall. 

The RISE app can work out your individual sleep need, so you know exactly how many hours is enough for you. RISE can also guide you through 20+ good sleep habits to help you get better sleep. 

And with 80% of RISE users getting more sleep within five days, it won’t take long to feel the benefits. 

Summary FAQs

Is 6 hours of sleep enough for one night?

No, six hours of sleep isn’t enough for one night for most adults. Most people need around eight hours of sleep. You may feel fine after six hours of sleep, but really, everything from your energy levels to your health and mental performance will be impaired.

Is 6 hours of sleep enough for a teenager?

No, six hours of sleep isn’t enough for a teenager. Research suggests teenagers need eight to 10 hours of sleep a night. And some may need even more. Not getting enough sleep can lead to low energy, poor mood, and lower mental and physical performance and health.

Is 6 hours of sleep enough to build muscle?

No, six hours of sleep isn’t enough to build muscle. Most people need about eight hours of sleep. You can build muscle faster when you get enough sleep. Research shows that sleep deprivation, even for one night, is enough to reduce muscle protein synthesis by 18%.

Why am I still tired after 6 hours of sleep?

You’re probably tired after six hours of sleep because you need more than six hours. Most of us need about eight hours of sleep. If you still feel tired after a full night’s sleep, sleep debt, being out of sync with your circadian rhythm, a sleep disorder, or a medical condition may be to blame.

Can I sleep 6 hours and take a nap?

You can sleep for six hours and take a nap, but sleeping for longer at night is better as sleep works best when it’s uninterrupted. However, if you can’t get enough sleep at night, sleeping for six hours and taking a nap can help you catch up on lost sleep and boost your energy levels. It shouldn’t be something you rely on, though, as getting six hours of sleep and taking a nap is probably still not enough to meet your sleep need.

Is 6 hours of sleep good?

Six hours of sleep is not good for most adults. Most of us need about eight hours of sleep, and some need even more. Only getting six hours of sleep can lead to low energy, impaired mental performance, poor mood, and health issues like weight gain, high blood pressure, and type 2 diabetes.

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

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