How Much Sleep Do I Need? – This Is What Science Says

Knowing how much sleep you really need can be difficult, but the experts have spoken and this is how much you actually should get every night.

Updated: June 15, 2020

You know the feeling. It’s 7 am, that dreaded sound of your alarm clock fills the room, and you poke the snooze button for the third time in a row.

You are hoping that the extra ten minutes in bed will somehow make you feel incredible when you finally wake up.

Shame, it won’t. Because you do the same routine every morning and you still feel terrible.

But why?

If you know it won’t make you feel any better, what’s the point in sleeping more?

Because you’re tired, duh.

The average amount of sleep most people get is 7-8 hours per night, which is recommended by experts. If that’s you, yet you still feel like death when you get out of bed, then keep reading.

Every adult is different when it comes to sleep. Some people can survive on 4-hours, while others need 10-hours +.

The critical factor is understanding how much sleep YOU need. Not the average person. Once you do that, you’ll be able to fall asleep faster, stay asleep longer and wake up feeling energized.

Ready to uncover just how much sleep you need?

Let’s do this.

The Biology of Sleep: Why Is It Important?

Without it, you’re dead.

Just like water, it’s vital for us humans to sleep, every day without fail. Sure you can work a few late nights in the office or party into the early hours. But what you can’t do is not sleep.

We need it to function at our very best, both physically and mentally. If you don’t get enough, there are several serious risks associated with sleep deprivation:

  • Weak immune system – you’ll catch both bacterial and viral infections (such as the common cold, hay fever, even potentially fatal viruses) more frequently. A weaker immune system can cause much lower energy levels than usual and influence your body in similar ways to stress.
  • Easily irritated or sulky behavior – the phrase “Look who woke up on the wrong side of the bed this morning.” best describes how you’ll feel after little to no rest. It can also lead to depression if you’re not careful.
  • Increase in stress – your capacity to handle high pressured stressful environments or situations will diminish drastically. So you can expect more outbursts and less of an emotional balance.
  • Exhaustion, laziness, and a shortage of motivation – you will see much lower productivity levels. Your day will be slow, tiresome, and caffeine will most be your go-to stimulant.
  • An early death – yes, you read that correctly. Sleeping less (or in some cases longer) than you need to, might just put you in an early grave.
  • Severely impaired brain activity – expect memory difficulties, concentrating for extended periods, or working on tasks that require creativity. A study suggests that without sleep, your brain’s ability to process emotional and cognitive functions are massively disrupted, causing degraded mental health.
  • Lower sex drive – if you enjoy sex, then sleeping less can affect your sexual desire. A study on sexual arousal showed that sleep-deprived women had lower next-day genital arousal, so decreased their chances of sleeping with their partner. Other research suggests that men with higher levels of testosterone were unstimulated by sex.
  • Enhanced risk of severe health problems – you’re exposing yourself to society’s most significant health concerns and killers. This includes strokes, high blood pressure, diabetes, heart disease, cancer and Alzheimer’s disease.
  • Lack of problem-solving skills – your memory recall will become impaired. So much so that the ability to solve any complex problems will be temporary if not impossible, the less REM sleep you get.
  • Impaired motor skills – This research paper indicates that just one night of sleep deprivation can cause an increase in reaction times and a higher number of errors. Hallucinations and delirium are also common in chronic sleep deprivation.
  • Premature skin ageing – A British Association of Dermatologists study found that the less sleep you get, the more your skin will age. Progressed signs of natural ageing (you age faster), decreased skin barrier function (protection from toxins) and lower satisfaction with appearance (you look older).

Are you convinced that sleep is important now?

It’s both intriguing and terrifying to think that so much can happen to your body and brain just from not getting the right amount of restful sleep.

5 Signs you are Not Getting Enough Sleep

Some sleep deprivation signs are obvious, and others not so much. Here are the most common red flags you need to be aware of. These warning signs are telling you that your sleeping behaviors need a drastic change.

Woman sleeping on a train.
Are you getting enough sleep?
  • No energy upon waking – do you wake up with energy, jumping out of bed and ready to start the day? Or do you let out a huge groan, falling out of bed? If you answered the latter, then this is a good indication that something is wrong.
  • Sluggish throughout the day – do you need umpteen cups of coffee to keep you at an average energy level through the day? This could be a sign that you’re both addicted to caffeine and fighting fatigue. Terrible for your brain and body.
  • Hit the snooze button – when the alarm goes off, do you slap the snooze button convincing yourself that all you need is five more minutes sleep? A massive flag that you’re not getting the quality sleep your body craves.
  • Oversleep on weekends – the workweek is over and the weekend is here, do you spend most of the morning in bed, trying to catch up on lost sleep? This is a worrying sign, and a pervasive problem called sleep debt.
  • Focus and memory – do you find it incredibly challenging to focus on one task at a time or understand what you just read? Mental fatigue will rob you of your time by making you do the same thing over and over without actually completing a task. Your brain will feel fuzzy, and you’ll be unable to concentrate.
  • Hungry all the time – can’t stop munching on the lunchroom snacks? That’s because ghrelin (the ravenous hunger hormone) is controlling your eating behaviors. Quality sleep fuels the body, by repairing damaged cells and keeping a healthy hormonal level in your body. Lack of sleep will leave an energy void, that will be filled by overeating and snacking the following day.
  • Weight gain – all that extra eating is going to add excess fat around your belly. What sleep deprivation also does is cause metabolic dysregulation and lower leptin levels (an appetite suppressant hormone). This will lead to a hormonal imbalance.
  • Impulsive behavior – are you making snappy haphazard decisions that are causing you to make more mistakes? Yep, that’s a big sign you’re deprived of sleep. Your brain will search for the easiest route at all times, making the word no, almost impossible to say.
  • Nodding off – are you finding it hard to stay awake on the train, behind the wheel or at the office? That constant feeling of being able to sleep anywhere at any time is a big hint.

Quality Sleep Matters MORE Than Hours Slept

Thre are so many mental and physical health benefits to sleeping that it’s almost unbelievable. Various medical professionals agree that sleep is essential to vitality. But what they fail to communicate to us regular mortals, is that quality of sleep is far more critical than quantity.

When you start to focus on quality over a recommended “one size fits all” hours approach, that’s when radical shifts in mental clarity and physical stamina begin to happen.

Take this biological clock study, for example. It states that three pre-industrial societies from Tanzania, Bolivia, and Namibia all survived on 5-7 hours of sleep, dozing off after the sun had set and waking at sunrise.

Huh, that would suggest circadian rhythm sleep is more important than hours in bed then. So why is 8-hours the minimum amount of sleep advised?

Another study on over 1.1 million people shows that sleeping longer than 6.5 hours per night is not only a waste of time but could be detrimental to your health. The study by Dr Daniel F. Kripke states that they didn’t find any empirical evidence relating to health that supports sleeping 8 hours.

If that didn’t surprise you, then this will.

Just one night of good uninterrupted sleep can improve your ability to learn new motor skills by 20%.

Not impressed? How about this.

Better quality sleep can help you to gain insight into complex problems by as much as 50%.

If you’re still shaking your head and saying “No, no, no… I need my 8 hours” then you’re not alone. This myth has been promoted for many years. But as the saying goes; “If you believe it, then it’s true”.

Seriously though, you need to question your beliefs when you start seeing studies like this that say 5 hours of sleep is “slightly safer” than 8 hours for preventing cancer.

Thre are more and more studies proving that the longer you sleep, the worse it is for you (in most cases), so now that I have your attention let’s move on.

Why Don’t you Get Enough Sleep?

If you’re not getting enough shuteye, there’s usually a reason why. Before you can understand how much you need to live an optimal life, you first need to know what the root cause is behind a lack of or bad quality sleep.

Here are the most common reasons why most people don’t get enough:

  • Drug side effects – if you’re taking medication due to an illness or persistent health problem, a side effect of that medication can be sleep difficulties.
  • Sleep disorders – insomnia, apnea, restless leg syndrome and many other sleep disorders can profoundly impact a quality nights rest. With 50-70 million Americans suffering from at least one disorder, it’s easy to understand why so many people struggle with sleep.
  • Caffeine – the most consumed stimulant on the planet, it’s usually in the form of coffee. But you can find caffeine in a lot of unexpected foods and drinks. However you consume it, caffeine entering your body between 3 and 6 hours before bedtime will cause sleep problems.
  • Stress – it’s been shown that stress can be very harmful to the human body in more ways than just sleep. Stress initiates the HPA axis, which is responsible for stress response in the central nervous system. An increase in this mechanism means a terrible night in bed, followed by an even worse day.
  • Shift work – security guards, entertainers, doctors/nurses, air traffic controllers, the list goes on. If your job demands rotational shift work, you can bet your sleep will be affected.
  • Personal obligations – a new addition to the family is a great way to throw your sleep out of whack. Also caring for a family member that needs constant care, can be a massive bearing on your sleeping habits.
  • Jet lag – the term “jet lag” is used to describe a deprived sleep state when your body clock is irregular. It’s caused by a sudden change in your sleep pattern. It’s said that for every hour in time-zone difference, you can expect that to translate into one day of jet lag recovery. So, a country that’s five hours ahead of you will take you five days to get back into a regular sleep routine. Crazy right?

That’s why you don’t get enough. Now let’s fix it.

How to Sleep Better in 9 Simple Steps

Getting a quality nights sleep is quite easy. Use the steps below, one per week and write down in a sleep diary (more on that later).

Pro tip: Taking one step per week will give yourself enough time to test what works for you. Doing them all at once will overwhelm you, giving a sense of frustration and leading you back to the bad habits you have now.

  • Sleep schedule – choose a specific time for what works best with your circadian rhythm and lifestyle. If you need to wake up at 7 am to be in the office for 9 am, and you need 6.5 hours to feel fully rested, then you should be in bed by at least 12:30 am. Erratic sleeping patterns have been linked to inadequate sleep.
  • Bedtime ritual – a set routine for bedtime is essential (not just for children). Set aside one hour before your ‘go to bed’ time and use that to unwind. This could be with a hot cup of chamomile tea, reading a fictional novel, while in a warm bath submerged in relaxing bath salts. However you choose to relax, is entirely up to you.
  • Exercise – more and more research is confirming the role that physical activity has on sleep. In this study on 2,600 men and women, it revealed that 150 minutes of light to substantial exercise per week, provided a 65% improvement in sleep quality. Just 20-30 minutes a day of running or cycling will be enough.
  • Good sleep environment – having a relaxing and consistent sleep environment is pivotal to improve sleep. Make sure you have a modern mattress that supports your body. A great mattress can help with musculoskeletal sleep-associated pain. Buy some blackout curtains so that no light can enter. Keep the room temperature at 16-18°C (60-65°F), which is perfect for cooling your body throughout the night. Thermoregulation is one of the critical factors in impacting sleep.
  • Avoid silent sleep stealers – it’s believed that a healthy diet can influence sleep quality. But what about the silent sleep stealers, such as alcohol, caffeine, medication and nicotine/tobacco? Most people have no idea about the hidden ingredients and chemicals in some of these items. Take alcohol; for example, a popular myth is that it can aid sleep, but studies have shown this not to be the case. It actually hinders sleep, by blocking the REM stage in your cycle, interrupting your circadian rhythm and producing conflicting brain wave patterns.
  • No electronics – do you have a habit of taking your phone to bed? – Research confirms that blue-light from your phone or computer screen is profoundly affecting your sleep quality by messing with your circadian rhythm. Use blue-light filtering software or wear light blocking glasses an hour before bed.
  • Don’t over nap – A quick nap in the afternoon to catch up on your lost sleep from the night before sounds like a great idea. But in reality, you’re going to wake up from your nap feeling worse. Unless you track your sleep cycles and wake up in phase one or two (the lighter sleeping phases), then you should be fine.
  • Supplements – “hacking” your biochemistry is one of the easiest ways to improve your sleep. Supplements work by increasing the nutrients in your body that are running low, to restore the balance. Magnesium, melatonin, potassium, 5-HTP, L-tryptophan and GABA are all supplemental options you should consider. Each one has been studied extensively and shown to help promote deep sleep (the quality kind).
  • Meditationproven to help with the quality of sleep, mindful meditation is simple to do. Take 5-10 minutes before bed to lay down with your eyes shut and focus on your breathing. Breath in slowly for 5 seconds and out slowly for 5 seconds. When your mind begins to wander off, concentrate on your breathing and keep repeating the process until you feel fully relaxed.

How Much Sleep do I Need for my Age?

Sleep is subjective and different for everyone. It’s essential to find a schedule that works best for you, but using the recommended duration times (advised by the Sleep Health Journal) below are a good starting point.


Newborns (0-3 months)

  • Hours needed: 14-17

A newborn baby’s sleep schedule is essential to their health. They are in the process of setting a circadian rhythm and will be polyphasic, sleeping multiple times throughout the day. Usually in 2-4 hour slots. At the one year mark, a natural sleep pattern will begin to immerge, and they will get used to going to bed at nighttime when it’s dark.


Infants (4-11 months)

  • Hours needed: 12-15

As they approach the 4-month mark, their circadian rhythm is still being established, even though hours needed are slightly less. Babies always move and vocalize during REM sleep for the first year of their lives. Unlike older children and adults who experience sleep paralysis during REM, babies spend a lot more time in the fourth cycle.


Toddlers (1-2 years)

  • Hours needed: 11-14

Around the age of 1-2 years, toddlers are entering the biphasic sleeping phase, so are more likely to sleep a couple of times in 24 hours. Once in the evening and once during the afternoon.

A solid sleep pattern should now be established at night, and they will know when it’s time to go to bed.


Preschoolers (3-5)

  • Hours needed: 10-13

Children at this age will generally resist going to bed because they are too busy playing. Even though they feel tired, they won’t give in, which is why a routine is so important.

If they are attending pre-school, they will be napping in the early afternoon, usually after lunch for two or so hours.


School-age children (6-13)

  • Hours needed: 9-11

Napping at this age is uncommon, but not unusual. Sleep problems or disorders may have started to develop too, such sleep apnea, sleepwalking, parasomnia symptoms and restless legs syndrome.

They should be well adjusted to a natural routine of sleeping once per day from night until morning.


Teenagers (14-17)

  • Hours needed: 8-10

Teenagers are notorious for being lazy and moody. Their hormones are developing due to fluctuations in testosterone, estrogen and progesterone. So this will have a significant effect on their energy levels, causing them to go to bed and wake up later than adults.

During puberty, sleep patterns change rather dramatically, and studies are linking adolescent sleep to maturing brain behavior. As a result, teenagers are sleep deprived as a result of society telling them to go to school at a specific time. This makes them more depressed and tired during school hours, making it harder to study.

15-year-olds, in particular, have shown the most significant drop in total sleep. One study shows a massive 40% of teens not getting the suggested 8-10 hours per night.


Young-Middle Aged adults

  • Hours needed: 7-9

Both young (18-25) and middle-aged (26-64) adults need around 7-9 hours of sleep. Although as mentioned above, studies are now confirming that adults need less bedtime than we think, so 5-7 hours could be enough.

There are many variables to consider in an adults life that will impact their rest. Things like a stressful job, poor diet, minimal exercise, lousy sleep environment and overuse of electronics can all add up to very detrimental sleeping habits.

Another thing to consider is each person has a different biological chronotype. In other words; you’re either a morning person or a night person. So your sleep schedule will be affected depending on your job hours and other commitments.


Older adults (65+)

  • Hours needed: 7-8

Seniors are much more likely to suffer from a bad nights rest, as a result of health issues. One of the most common problems is restless leg syndrome (RLS) which affects 10-35% of seniors. It can also cause periodic limb movement disorder (PLMD) which is chronic leg cramping or jerking.

It’s well documented that slow-wave sleep (deep sleep) declines with age also, making it more difficult to feel rested when you wake. It’s still unknown whether this is because of neurodegeneration or it’s a symptom of bad health.

Data shows that the pineal gland (the gland that releases hormones for sleep) gets worse at doing its job as you age.


How to Find out the Exact Amount of Sleep You Need

Here’s what we know so far; the amount of hours you sleep is dependent on many factors. Now, you should take the findings from experts on both sides of the spectrum and test them thoroughly to see how many hours you need at night to feel optimal.

To do that, you need the following two things.

Stage/Cycle monitoring app

Choose an app to monitor the four stages of your sleep, and when you enter each phase. Doing this will help to determine how many hours of REM sleep you get (the deepest stage) and when you can wake up after re-entering the first stages (the lightest stages).

Diary to track bedtime habits

Use a sleep diary to keep track of your routine, habits, disturbances and overall feelings when you get up. You can either use a notebook or just create notes on your phone.

Answer the below questions as soon as you wake up:

  • How long until you fell asleep?
  • Did you need an alarm to wake up?
  • Did you hit the snooze button?
  • How do you feel energy-wise?
  • What did you eat before bed if anything?
  • Did you have any caffeine yesterday?
  • What time did you go to bed?
  • How many hours did you sleep in total?

After a few weeks of keeping a diary, you’ll start to see patterns emerge that build an overall picture.

Frequently Asked Questions

These are the most common questions that most people have when it comes to finding out how much rest they need.

How much sleep is too little?

Aside from differing opinions amongst experts on the hours needed per night, one thing is certain as of right now, based on the evidence. Anything less than 4 hours a night is not enough to both repair the body and replenish the brain.

Is it ok to get 5 hours of sleep?

Yes. It’s perfectly safe, and research has proven this to be the case.

How much sleep do adults need?

It’s recommended that adults get between 5-9 hours per night for an optimal amount of sleep, anything less or more is considered unsafe.

How long can you go without sleep?

You will enter the beginning sleep deprivation stages within the first 24 hours. In terms of survival, the longest recorded time in history without sleep was 264 hours (11 days), but what’s the point? If you can’t function properly, then there’s no reason to put yourself through that.

Is too much sleep bad for you?

Yes. The world’s biggest sleep study to date showed that participants who slept 7-8 hours performed better cognitively than those who overslept. It seems that the more you stay in bed, the worse your health is, both physically and mentally.

How much sleep do I need for muscle recovery?

If you want to increase muscle mass, then 7-9 hours is recommended. Rest is one of the best forms of muscle recovery, as it enhances human growth hormones and protein synthesis.

Will more sleep get rid of dark circles?

No. Although lack of sleep can contribute to tired-looking eyes, it’s actually a myth that it causes dark circles. The cause is a deficiency in iron and largely down to hereditary reasons.

How much sleep should I get while pregnant?

Sleeping during pregnancy is going to be reasonably uncomfortable at times. Frequent bathroom breaks, tossing and turning, leg cramps, RLS, morning sickness at night and heartburn. You will be sleep-deprived, so should aim for 7-8 hours per night to avoid fatigue throughout the following day.

How many hours sleep do I need to lose weight?

If you’re overweight, 8-9 hours should be the ideal amount. Research shows that sleeping less than 8 hours per day can decrease fat loss by 55%. Levels of ghrelin increase the less you sleep; the result is much worse eating habits and more extended periods of hunger.

Conclusion and Recap: How many hours of sleep do I need?

How much sleep you need depends on your current state of health, work schedule and life commitments, which all contribute to stress levels, weight and sleeping disorders. These factors, in turn, indicate how much sleep you need.

You should focus on enhancing the quality of your sleep in a 5-9 hour window. If you’re looking for a definitive answer to how much sleep you need, you will find it within your tests and not an average statistic.

So here’s what to do next:

  1. Start tracking your sleep cycles.
  2. Note down everything in your sleep diary.
  3. Begin optimizing your nightly routine until you reach the ideal amount of hours that make you feel great.
  4. When you find your ideal sleep schedule, stick to it. Avoid sleep loss at all costs. Your health depends on it.