How Much Sleep Should You Have?

Written by
The Manual Team
Medically approved by
Dr Earim Chaudry
Last updated
15th February 2021

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In 30 seconds

Sleep is good for us. This is a fact that’s pretty well acknowledged. It helps us fight disease, concentrate, and consolidate our memories – as well as a whole lot of other things besides.

But how much sleep should you have? According to most medical advice, adults should aim for between 7 and 9 hours of overall sleep a night. For children and young adults, that should be more. And although older people are thought to sleep less, they still should really be getting 7 hours or more too.

And deep sleep? That’s the really restorative part of your nightly sleep. It’s thought that you get about 2 hours of deep sleep if you sleep for 8 hours during the night. And that should be enough to perform at your best.

How Much Sleep Should You Have?

Some people need to sleep for a good ten hours before they feel fully rested. Others claim to be happy on as little as four hours and a few cups of coffee. We’re all different – certainly. Yet, the benefits of sleep are true for us all.

So, how much sleep should you have? According to the NHS, for example, the recommended amount is 6 to 9 hours of sleep per night. Depending on who you are, this is enough for you to feel rested – and to enjoy the benefits that sleep brings.

But they should ideally be uninterrupted. While after a long night, a couple of naps in the day might feel necessary, this isn’t always restful sleep. Rather, to benefit, you need to go through all the stages of sleep in the sleep cycle: light sleep; rapid eye movement, or REM sleep; and deep sleep.

Here, we’re going to look at what you actually need to know about sleep – and how much of it you should be getting. We’ll give you some pointers on how to get better sleep too.

Why Do We Sleep?

Before we get onto how much sleep we need, why do we even sleep in the first place? It’s a tricky question – and it is one that has puzzled and fascinated scientists for centuries.

As a result, though, there is no one clear-cut answer that solves the puzzle of the science of sleep. Rather, there are lots of different theories about why we do it. And the truth is probably that all of them are relevant. Let’s take a quick look at some of these benefits of sleep.

During Sleep, We Repair and Restore

Sleep helps us to repair things that become weakened or damaged during the day. You probably feel this to be true. When we do a hard workout, for example, sleep helps us to recover, to regain strength again – and to heal any muscular tears or strains. You feel it the next day.

Yet, the restorative function that your sleep works in much deeper ways than tissue repair too. Protein synthesis tends to happen while we sleep – as well as the release of key growth hormones. Both of these help your cells regenerate.

Crucially, your immune system needs you to sleep too. Sleep deprivation causes the release of stress hormones, which dampen your immune response – and it can cause immunodeficiency in the long run.

It Helps Us Learn and Perform Well

Sleep also appears to be essential for brain function. It helps us to learn new things and to be able to recall information when we need it. And a lack of sleep affects our ability to make judgments and choose the best course of behaviour too. This way, it actually changes your character.

Scientists don’t really know why sleep affects brain function in this way. Yet, it is thought that, during the day, your brain activity builds new pathways between different parts of the brain. During sleep, these are consolidated. This is why sleep helps memory too. 

Sleep Helps Us Conserve Energy

During sleep, we enter a deep rest mode. Our heart rate slows, our body temperature drops, and our brain waves slow down too. As a result, we use less energy, which means we need to eat less. Which was quite important once upon a time when we had to hunt for food.

Simply, we don’t want to be running at full steam the whole time. This doesn’t necessarily make sense when the hunt for food is as simple as walking to the fridge. But it would have been. Because, when you think about, it is not all that easy to hunt at night.

What is Deep Sleep?

In all this, not all of the different stages of sleep have the same effects. While deep sleep is believed to be the time when muscle growth and repair takes place, REM sleep tends to boost your brain power.

So, what are these stages of sleep? They are often referred to in 1-4 stages. Or else as REM and non-REM (nREM sleep or non-Rapid Eye Movement) sleep.

Awake Time. The ‘zero’ stage of sleep is actually awake time. This is how you are during the day, obviously. But it is also the name for those little moments during the night when you come back to consciousness.

Light Sleep. This comprises the first stage and second stage – and this makes up the over half of your sleep time. It’s when muscles relax, breathing and heart rate slows, and body temperature drops. It is sort of a transition stage, in which you wake up easily.

Deep Sleep. During deep sleep – or third stage sleep – you are repairing your body. This is when cell and tissue repair occur and when the growth hormone is released. You flush waste from your brain too.

REM Sleep. Stage 4 is REM, the time when dreams are vivid. You become physically immobile, but your heart rate speeds up and your breathing too. At this time, your brain appears to be working to restore memory and learning functions.

How Much Deep Sleep Should You Have?

So, how much sleep should you have? And, specifically, what amount of deep sleep should you get?

We noted above that the recommended amount of sleep is about 6 to 9 hours. However, there is a bit more to it than just this. 

According to researchers at Harvard University, each of the different stages of sleep last a different length of time. The first stage (part of ‘light sleep’) lasts between 1 and 7 minutes. The second stage lasts 10 to 25 minutes. Then comes deep sleep, which lasts about 20 to 40 minutes, and then REM, for about the same length of time. 

The whole cycle lasts for about 70 to 120 minutes. However, you are supposed to pass through this cycle 4 or 5 times a night, as an adult. Each time that you pass through the cycle, the length of each stage will change. Together, this adds up to the average 7 to 9 hours. 

And how much deep sleep should you have? About 2 hours is believed to be sufficient. And if you get enough sleep overall, you should manage to achieve that.

How to Get Better Sleep?

Finally, what can we do to get better sleep? You can of course give yourself better Zs with the help of our Good Nights sleep solution. We combine all the best natural sleep ingredients: tart cherry, chamomile vitamin B6, and lemon balm – to help you get a more restful sleep.

And your quality of sleep is often the result of the actions you take and habits you have in the rest of your life. As such, there are straightforward steps that should improve your overall sleep quality.

#1: Try to Sleep at Night

It’s not true that sleep is sleep no matter the time of day you do it. Rather, the sleep you get at night is much more valuable than any naps or lie-ins. That’s because your circadian rhythm – your body’s internal clock – wants to be in sync with that of light and day. 

However, we’re sorry to those on night shifts who won’t be able to manage this. Replicating the conditions of darkness before bed – and natural light when you wake – can help.

#2: Cut Down on Caffeine 

We drink caffeine these days to keep us awake. But every cup of coffee we drink – particularly in the afternoon – can have repercussions for the quality of our sleep. It reduces overall sleep time and stops you getting into that slow-wave sleep that characterises deep sleep.

#3: Exercise

If we are sat inside on our computers all day, you can be tired – but not necessarily physically so. Doing regular exercise can simply just make you more tired, less stressed, and can get you to sleep more easily.

#4: Change Your Bedtime Routine

The lights of your devices – or the stimulation of television, for example – can keep you up. It just means you are not as relaxed as you could be when you hit the hay. Try to change things up a little: read a book or turn the lights low. Or, you could also have sex with your partner! It’s proven to help you sleep.

Key Takeaways

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So, how much sleep should you have? The science says 7 to 9 hours a night – depending on your age and personal needs. And deep sleep? 2 hours, in the context of sufficient sleep overall, is more than enough.

If you feel like you are not getting it, try to change your lifestyle. Cut down on caffeine and get moving – and try to change the way you go to bed. This has an impact we usually overlook.

References

  1. NHS-How to get to sleep: https://www.nhs.uk/live-well/sleep-and-tiredness/how-to-get-to-sleep/

  2. Pre-Sleep Protein Ingestion to Improve the Skeletal Muscle Adaptive Response to Exercise Training – Jorn Trommelen and Luc J. C. van Loon (2016). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5188418/

  3. Sleep deprivation and growth-hormone secretion – Klaus Lieb, Martin Reincke, Dieter Riemann, Ulrich Voderholzer (2000). https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(05)74304-X/fulltext

  4. Sleep and immune function – Luciana Besedovsky, Tanja Lange, and Jan Born (2011). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3256323/

  5. D TempestaA CouyoumdjianF MoroniC MarzanoL De GennaroM Ferrara – The impact of one night of sleep deprivation on moral judgments: https://pubmed.ncbi.nlm.nih.gov/21943064/

  6. Healthy Sleep – Natural Patterns of Sleep: http://healthysleep.med.harvard.edu/healthy/science/what/sleep-patterns-rem-nrem

  7. IanClark, Hans Peter Landolt – Coffee, caffeine, and sleep: A systematic review of epidemiological studies and randomized controlled trials: https://www.sciencedirect.com/science/article/abs/pii/S1087079216000150

  8. Michele Lastella, Catherine O’Mullan, Jessica L. Paterson, and Amy C. Reynolds – Sex and Sleep: Perceptions of Sex as a Sleep Promoting Behavior in the General Adult Population: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6409294/

While we've ensured that everything you read on the Health Centre is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. It should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.

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