Is 6 Hours Sleep Enough?


Fact Checked

Written by Phillippa Quigley

We all know sleep is important to us all. It is a key factor in being healthy and feeling re-energized each morning and throughout the day. However, how many hours sleep we get can differ from person to person. A lack of sleep can impact our health significantly. 

In this article we will look into whether 6 hours sleep is really enough. We will discuss how to have quality sleep, and how much is optimal for our health.

In short, 6 hours of sleep is not enough for most adults. Whilst you may feel that time-wise, enough hours have passed for you to feel like it should be enough rest. You will not be able to perform to your best ability with only this amount. 

Most people need a very similar quota of sleep each night. This does depend on your age, as it changes the older you get. If you’re not getting the recommended amount of sleep consistently (we all can have the odd disruption), then you should see a healthcare provider.

The average ideal sleep per night related to age is:

  • Newborns (up to 3 months old): 14 to 18 hours
  • Infants (up to 1 years old): 12 to 16 hours, napping hours included.
  • Children (1 to 5 years old): 10 to 14 hours, napping hours included.
  • School aged children (6 to 12 years old): 9 to 12 hours
  • Teenagers (13 to 18 years old): 8 to 10 hours
  • Adults (18 years and up): 7 to 9 hours

Quality of Sleep vs. Quantity of Sleep

Sleep is a basic human survival mechanism. It is that important. 

woman sleeping in bed

The quality and quantity of sleep that we get are both important to how rested we feel. However, often we can get confused by thinking that if we were to get 6-8 hours of sleep, then that is all that matters. 

But what if that 6-8 hours of sleep was full of restlessness, repeated episodes of waking up or symptoms of a sleep disorder eg; Sleep Apnea where you are gasping for air or snoring. This would result in you still waking feeling sleepy and tired. That would be classed as poor quality sleep despite the length. 

Good quality sleep means that whilst you are asleep you are sleeping well. Whilst we view sleep as a time where our mind and body will rest, they are in fact still active. Just not in a way that is of detriment to our health. 

When you are sleeping, our body’s will repair cells and restore energy. It goes through a detoxification process where the brain gets rid of toxic waste. Sleep also helps us regulate our emotions, which is why a lack of sleep tends to make us feel slightly more emotional than we would be normally. 

All these processes, take place during different stages of our sleep. We need to give ourselves time for these all to happen. Which is why our sleep is a balance of quantity and quality. With too little sleep, we don’t give ourselves enough time to recover, repair and restore. 

What are the Stages of Sleep?

There are four stages of sleep that our body goes through. The first three stages are known as Non-REM sleep, and the fourth stage being REM sleep. REM sleep is the most commonly known stage and is where we can experience having vivid dreams. 

The stages of sleep happen within sleep cycles, these cycles tend to last from 90 to 120 minutes each. An average adult will have 4-5 sleep cycles each night. 

Oura sleep tracking example
An example of how the sleep stages might look when tracked with an Oura ring

Stage 1: NREM N1

This is where you first fall asleep. It only lasts from one to seven minutes. N1 is where we transition from being awake to falling asleep. 

Our body and brains slow down and we can fall into a light sleep. If you were to be woken within Stage 1, you wouldn’t know that you had fallen to sleep. If left undisturbed, you would quickly move into the next stage. 

Within your body during this stage; you muscles would start to relax, your heartbeat and breathing rate slows down and our eye movements slow and roll. 

Stage 2: NREM N2

This stage is where we spend our longest time asleep during the night. Each cycle we enter, N2 becomes longer. You can be woken easily within this stage as you are still sleeping quite lightly. 

When we are in Stage 2, our body is in a more calmed state. Our breathing rate will have slowed even further, our eye movements have stopped and our body temperature will have dropped. Whilst this is happening, our brain waves show a new pattern. 

Stage 3: NREM N3

In this stage, you are finally entering a deep sleep. It would be hard to wake someone up when they are in this phase. Any sleepwalking tends to occur during Stage 3. 

During this stage your blood pressure will drop and your muscles will relax. Your brain shows a pattern of activity know as ‘Delta Waves’. These are known as  ‘long-burst’ brain waves, or people may refer to this type of sleep as ‘slow-wave’. 

This is an important stage of sleep as it is when your body and brain starts to repair, which is why if you can get lots of it you will wake feeling refreshed the next day. Your brain will be consolidating memories and things you have learned meanwhile your body will be recovering and growing. 

Stage 4: REM N4

Known as when your Rapid Eye Movement (REM) sleep occurs. This happens about 90 minutes after you first fall asleep and will reoccur every 90 minutes. 

Your brain activity will almost resemble it’s awake activity. Your eyes move around quickly, and your breathing and heart rate increase to nearly awake levels. During this stage your body is paralyzed temporarily, which is definitely a good thing as you don’t want to be acting out some of the vivid dreams you might be having!

You can dream in any of the stages of sleep, however that is less common and they would not be as intense as in your REM sleep.

REM sleep is essential for our cognitive functions as well as our immune system – it helps us to fight off infection, inflammation and illness. 

Let’s talk about ‘The Afternoon Slump’

If you’re asking yourself ‘Am I getting enough sleep?’ and you’re also finding yourself suffering from the afternoon slump, then you might be answering your own question! 

The afternoon slump is when you find yourself feeling exhausted, full of yawns, your sluggish and your energy levels have dipped. You might have lost concentration of whatever task you are doing and have zero motivation. 

We all will, to some point, suffer with an afternoon slump. After our lunch we could be suffering from a blood sugar low, if it got spiked with your choice of food. Maybe you have been working quite sedentary that day, and haven’t actually moved your body. These are two quite common causes of the afternoon slump which we can all experience.

If you are suffering with poor sleep, and you’re not getting enough then unfortunately you will be a prime target for an afternoon slump! It will more than likely be a lot worse than ‘a normal sleeper’. 

Here are some quick tips to help fight the afternoon slump:

  • Hydration: Make sure you are not dehydrated. This will make you feel sluggish, tired and it will affect your mood. Drink plenty of water throughout the day.
  • Move your body: If you have been sitting for too long, your body might get confused and think it’s time to rest and sleep. So take a break from your work, and talk a walk or have a stretch. Even better get outside for a little stroll – bonus points if this can be in a green space.
  • Eat Healthy: Try to stay away from foods that are high in sugar or refined carbohydrates. Pick fresh fruit or vegetables, foods high in fibre and protein. 

Why is 6 hours not enough sleep?

Now that we have discussed the basics about why our sleep is important and what the stages are, as well as what our body needs and does in each phase, let’s discuss why 6 hours sleep just isn’t enough for you to feel at your most optimal self.

Daytime sleepiness

We’ve discussed the afternoon slump, and it is a natural dip in our energy levels, but if you are feeling that slump significantly then something is up! It is more than likely that you are not getting enough sleep at night. 

Sleep deprivation can be a big cause of daytime drowsiness, as well as the quality of sleep you are getting. We now know which stages of sleep gives our bodies the repair and restoration, and if we aren’t getting enough then we will simply not feel rested or refreshed on waking. 

Symptoms of daytime drowsiness or sleepiness can be:

  • Slow reaction times
  • Memory problems
  • Unable to stay alert
  • Low mood
  • Poor behaviour
  • Irritable
  • Decision making difficulty

People who don’t get enough hours of sleep during the night can become used to their daytime drowsiness. Almost like their coping mechanism to get through the day is because they have an afternoon nap. 

The problem with an afternoon nap is that dependent on the length, it can seriously affect your circadian rhythm – and not in a good way. Small and quick naps, can be a mood booster. They can be increase your cognitive performance and alertness. You need to nap early afternoon and not for too long so that you don’t affect your sleep later in the evening. 

Ultimately though, the need for an afternoon nap, would decrease significantly if you were sleeping for the optimal amount of time in the night.

Lack of REM Sleep

We now know that REM sleep is hugely beneficial for our body and brain to restore and recover. It is also the final stage of our sleep cycle, of which we get an average of 4 -5 cycles per night. 

With REM sleep, within each cycle of sleep we have, the length of actual REM sleep we get increases. 

Each sleep cycle we have lasts on average from 1.5 hours to 2 hours long. However each cycle is not the same. During the first half of the night, we spend more time in deep sleep, with the second half being in REM sleep. 

Within a whole nights sleep, we spend only a quarter of it in total in REM sleep. In our first cycle, we only get about 10 minutes in REM sleep. This increases with each cycle. By the final sleep cycle we can have up to an hour of REM sleep. 

This is where the idea that if you sleep for only 6 hours of the ‘6 – 8 hour quota’ is still healthy starts to unravel. By cutting your nights sleep short by two hours, you are missing out on the most restorative part of your sleep. 

When your body misses out on it’s much needed REM and deep sleep, it will have an instant and long-term impact on your health and wellbeing. 

Creatures of habit

When you’re not getting the optimal amount of sleep each night, you will adapt. It will lead you into a false sense of security that you feel fine and that you can cope. 

For example, you’re a parent to a newborn baby – which we know is a guaranteed sleep stopper! You’re up in the night goodness knows how many times, but somehow after a few days you start to ‘cope’. This is an example where you know you don’t feel at your best but you can manage. 

If anything, this is a time where you really start to value your sleep and you cannot wait until you achieve undisturbed sleep again!

If you work in a job, with night shifts or long shifts, or maybe you’ve taken on extra work for a while. You will know that you’re sleep is going to be impacted for a while. You know it’s coming and that you won’t be at your optimal performance – but you adjust. 

These are a couple of examples where there are differing factors that are unavoidable for a time so you accept that your health might suffer for a short period.

However, if you are someone who consistently doesn’t get enough sleep each night yet feels fine, your body will have simply adapted too. This doesn’t mean that your body is coping as well as it would had you had more sleep. 

You may feel that 6 hours is enough sleep for you each night but the truth is that your body is suffering without you even knowing. Your performance and energy levels will be lower. Your slower reaction times and the ‘lack of energy’ feelings will become normal. As mentioned before your afternoon slump will probably be greater than those who get more sleep. 

Not sleeping enough can also affect your emotional and physical health. 

Sleep Deprivation

What actually is sleep deprivation? It occurs when you don’t get the amount of sleep you need. It can harm your mental and physical health, by causing extreme tiredness and affect your day to day quality of life. 

Ideally, an adult should be getting 7-8 hours of sleep a night. Sleep is just as important as oxygen and food for us to be able to function at our best. We know a lot more about the benefits it gives us, and at which stage of sleep we benefit from the most. 

Let’s take a look at how sleep deprivation can affect our health.

Mental Health

Most people will have experienced a change in their emotional state if they’ve had a lack of sleep. Sleep deprivation can have a significant impact on your emotions and mental capacity. You will suffer from a fluctuation in your mood, feel impatient and irritable. 

With chronic sleep deprivation you can feel quite manic. Other ways it can impact your mental health are:

  • Increased anxiety
  • Depression
  • Paranoia
  • Bipolar disorder


We know now that within our deep sleep and REM sleep our body will do its repair work. The immune system will fight infections. It produces antibodies to combat foreign invaders.

If you don’t get enough sleep, it will take you longer to recover from any sickness or disease. You can also go on to develop chronic illnesses. 

Digestive health

Do you ever find you are more hungry if you feel sleep deprived? There are two hormones called Leptin and Ghrelin. They are responsible for feelings of hunger and feeling full. Leptin is the hormone which tells our brain that we are full, this is reduced if we have a lack of sleep. Therefore, we will eat more. 

A lack of sleep can also affect the body’s tolerance for glucose and insulin production, therefore your ability to regulate blood sugar is compromised, leading to diabetes.

Cardiovascular health

Sleep keeps our heart and blood vessels healthy. Poor sleep can affect your blood pressure and inflammation in the body. Cardiovascular problems are higher in people who suffer with sleep deprivation. You are more at risk of heart disease, heart attacks and strokes. 

Nervous System

Without enough sleep, it is common for people to experience more pain. That is pain intensity and feel pain more easily. This increased pain can also cause sleep interruptions, which then creates an unhealthy cycle of poor sleep and increased pain. 

If you feel like you are suffering with sleep deprivation and it is becoming chronic and a health risk, you should contact your doctor. They will be able to assess your situation and guide you to treatment options. However, it may be a case of improving your sleep hygiene and habits. 

Increase your 6 hours of sleep

It is counter productive if the reason you sleep only 6 hours is because you can get more out of your day, if you stay up late and get up early. Whilst logistically it makes sense; more time in the day would equal more tasks complete. 

We know now that we simply cannot be as productive or are able to focus as best as we could if we had had more sleep. Meaning that, those extra two hours awake are better spent asleep as you will be more productive and focused after a longer night’s sleep. 

Some factors that can make it difficult to improve the amount of sleep we get include:

  • Work: Working shifts can make it hard to sleep for a good amount of hours when you having to sleep in the daytime.
  • Social: You might have ongoing social obligations that impact getting to sleep at a reasonable hour
  • Substance use: Alcohol and drug use affect your body’s natural ability to get to sleep and how deep you can get to sleep.
  • Prioritizing sleep: You may not view sleep as a high priority, or that it is part of a bigger picture for your overall health.
  • Sleep disorders: Sleep can be impacted if you suffer from any sleep disorders such as; insomnia, sleep apnea or restless leg syndrome. 

Some of these we are able to address easier than others. If sleep is something you haven’t included in your approach to good health, then you will now see the impact it can have on your overall health and wellbeing. By making it a high priority you will see and feel the impact it will have. 

Changing your sleep habits can take time. If you feel you may be suffering with a sleep disorder or need support with any of the other factors affecting your ability to improve your sleep, then seek support from a healthcare provider. 

Sleep improvement recommendations

To help improve your sleep hygiene, try some of these;

Bedtime routine: Think about the time you go to bed. Set a new routine, and stick to it. 

Sleep environment: Is your bedroom a relaxing place to be? Make it quiet, calm and dark in the evenings to help you relax and fall to sleep easier. 

Naps: If you do need an afternoon nap, make sure it is early and no longer than 30-40 minutes. 

Move your body: Move regularly and get outside when you can. Getting outside in the morning sun helps your circadian rhythm. This can be walking out into your back garden in your pajamas!

Healthy choices: Cut down or avoid alcohol consumption. Avoid caffeine after lunchtime and try not to eat rich meals close to bedtime. You should also look to ensure your nutrition is on point, certain vitamins and minerals aid our ability to sleep and the quality of it – for example, those using a high quality magnesium supplement might find they enjoy improved sleep if they were deficient in the mineral.

Blue Screen: Put down your phones and tablets at least half an hour before you want to get to sleep. 


It is clear that 6 hours of sleep is not enough for us. We need a full night’s sleep to make sure we are having enough cycles to get the optimal amount of deep and REM sleep so that we feel as refreshed as possible.

Our body and brain need all this time to repair, restore and process so that we can function at our best the following day.