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There’s plenty of debate about how much sleep we really need. We break down the recommended hours by age and how much of that should be deep sleep.
10 Min Read | By Shannan Humphrey
Last Modified 20 January 2025 First Added 21 July 2021
Reviewed by Sleep Expert Sammy Margo
“The key is to find out what works for you.”
How much sleep we need depends on a mix of factors, like age, genetics, lifestyle, our sleep cycle and activity levels, so there’s no one-size-fits-all answer. That said, the general rule is that the younger we are, the more sleep we need. While toddlers (1-2 years) need 11-14 hours, most doctors agree that adults (18-60) should aim for 7 hours or more. This is because toddlers are still in the process of growing, and sleep is vital to support growth and brain development.
So, let’s examine the number of hours we should spend sleeping, what can affect it, and how to determine what’s right for us.
Technically, yes! While 8 hours works for many, sleep needs are highly individual. The amount of sleep you require depends on your physical and emotional health, lifestyle, and even genetics. Some people may thrive on 6 hours, while others need 9 or more.
Interestingly, the 8-hour rule is not as natural as we think. In his new book How to Sleep Like a Caveman: Ancient Wisdom for a Better Night’s Rest, psychologist Merijn van de Laar explains that the 8-hour sleep cycle was actually invented during the Industrial Revolution. Before then, people’s sleep was more flexible and in sync with natural rhythms, often with segmented periods of rest. Van de Laar suggests that instead of forcing ourselves into a rigid 8-hour schedule, we should listen to our bodies and adapt our sleep habits to fit our own needs—just as our ancient ancestors did.
Your age is the most significant factor determining how much sleep you need, although there’s no magic number as – that’s right – everyone is different. The key factor for understanding how much sleep you need is to listen to your body.
If you find yourself groggy each morning, you may need to alter how many hours you get each night. That said, a good first step is using the recommended hours as a starting point.
These are the recommended hours of sleep by age group, according to the Centre for Disease Control and Prevention:
While it’s advised to aim for a rough quantity of sleep, quality is also important for feeling rested and allowing the body to rejuvenate.
Deep sleep is a vital stage of your sleep cycle, helping with cell repair, growth, and energy restoration. It’s arguably the most important phase and a big factor in whether you wake up feeling refreshed or groggy.
Again, the amount of deep sleep needed can vary from person to person, but on average, adults should achieve around 1.5-2 hours of deep sleep per night. This equates to roughly 20-25% of your total sleep time.
Learn more about deep sleep and why it’s important.
REM (Rapid Eye Movement) sleep is when your brain consolidates memories, develops your central nervous system, and helps regulate emotions. It’s also the stage where dreams happen.
Like deep sleep, there’s no exact recommended amount of REM sleep. However, studies suggest it makes up about a quarter of our total sleep. For infants, it’s even more, with around half of their sleep being spent in REM.
Sleeping may seem like your time to relax, rest, and dream; however, sleep has more impact on your health and lifestyle than you might think. Your quality of sleep is directly linked to and affects how you feel during the day and your physical and mental health. Here are several reasons why a good night’s sleep is important:
Not getting enough sleep can have a big impact on both your body and mind. It can affect your mood, making you feel irritable or anxious and can lead to impaired cognitive function, impacting your ability to make decisions, consolidate memories and concentrate.
Over time, a lack of sleep can also weaken the immune system, leaving you more susceptible to illnesses. A continued lack of sleep is even linked to a higher risk of serious health issues, such as heart disease, diabetes, and weight gain.
If you regularly don’t get enough sleep, you could end up with sleep deprivation. With this, your body will likely signal that you need to sleep more. These symptoms include:
If your sleep is interrupted a lot, you may need more hours of sleep to compensate for the lack of quality sleep you’re receiving, which is referred to as “sleep debt”. It means that there’s a discrepancy between how much sleep you need and how much you’re actually getting.
Unfortunately, it’s fairly easy to accumulate sleep debt. Even missing an hour every day can add up to an entire night’s worth of sleep lost. According to research, it can take up to 4 days to recover for every 1 hour of sleep debt.
If you spent the night tossing and turning or stayed up too late doom-scrolling, then you may feel exhausted when your alarm goes off. Of course, you can use caffeine, power foods, and even a nap to shake the grogginess, but it won’t make up for the lost time. Thankfully, you can recover from sleep debt with some good habits. Consistency is key when it comes to getting decent slumber, so if you do have a few bad nights, it’s important to get back to a healthy routine as soon as possible.
To get started, read our article on how to sleep better at night.
Surprisingly, yes, you can get too much sleep. Oversleeping can leave you feeling groggy and tired, even after a full night’s rest and is known as sleep inertia. It’s also been linked to a higher risk of health problems like heart disease, diabetes, depression, and even a shorter lifespan. If you’re regularly sleeping longer than usual and still waking up feeling drained, it might be worth looking into any underlying health issues.
However, scientists have actually identified 2 genes which allow some people to feel well-rested with short sleep (6 hours or less) and not get the usual negative side effects of sleep deprivation.
Do you relate? Find out more about short sleeper syndrome.
If you’ve ever enviously watched your pet snooze all day and wondered if you should have a quick kip, too, then we’re here to tell you that napping can have some great benefits. While humans have evolved to sleep more efficiently and so don’t require as much sleep as other animals, sometimes a nap is just what you need. Take a look at our guide to napping to find out more about the benefits, the ideal length, and when is best to get your shut-eye into your schedule.
If you consistently feel so sleepy during the day that you can’t focus or stay awake, you’re probably lacking restful sleep the night before. Try to fix your night time routine, and don’t let yourself nap in the late afternoon or evening, as this can disrupt your sleep patterns.
Want to know where your sleep habits stand compared to the rest of the nation? In our UK Sleep Survey, we found people, on average, spend 6 hours in bed actually sleeping, a 1.7% increase since 2022:
Find out more sleep stats and insights in the full UK Sleep Survey 2024.
Getting yourself into a routine and adopting these healthy habits during the day and at night can help you get more sleep. We’ll explore some tips below:
During the day:
Before bed:
If you struggle to get enough sleep or don’t feel rested, there are plenty of reasons and remedies. In fact, this is what this whole blog is about. We want to help you understand your body and sleep better at night. Browse our articles below on some of the most common sleep problems that might keep you awake and find some solutions.
Remember, if you struggle with chronic under or oversleeping, then it’s important to contact your GP to see if there is a more serious underlying cause.
See all articles by Shannan Humphrey
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