Is 5 Hours of Sleep Enough? It’s Highly Unlikely (2024)

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.

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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.

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.

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What’s the Recommended Amount of Sleep?

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?

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.

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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.

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How to Get Enough Sleep?

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.RISEhas 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!