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Sleep is a regular period of rest which allows the brain and body to slow down and engage in processes of recovery. Find out more about how sleep works, why it’s important and how to improve your sleep.

Sleep is a regular period of rest which allows the brain and body to slow down and engage in processes of recovery, promoting better physical and mental performance the next day and in the long-term. What happens when you don’t sleep is that these important processes are short-circuited. This affects thinking, concentration, energy levels, and mood. As a result, getting enough good quality sleep is crucial.

Everyone is different

It is important to remember that sleep is very individual and there is no right or wrong way to do it – every person is unique and will have a sleep cycle and sleep preferences that suit them.

Sleep is the golden chain that ties health and our bodies together.

Thomas Dekker, (1572-1632)

How sleep works

You have internal body clocks that control when you are awake and when your body is ready for sleep. These clocks have cycles of 24 hours on average. As you fall asleep, notable changes start to affect both the brain and body: body temperature drops, brain activity ramps down, and heart rate and respiration slows as well.

There are four stages of sleep divided into two categories. The first three stages fall into the category of non-REM (rapid eye movement) sleep. The fourth stage falls within the category of REM sleep. REM sleep stage is most essential for the brain, enabling key functions like memory and learning.

Stage 1 and 2

Stage 1 of sleep is when you have just dozed off, and it usually lasts 1-5 minutes. In this period,  we drift in and out of sleep and can be awoken easily. Our eyes move very slowly and muscle activity slows. 

You then transition into stage 2, which can last between 10-60 minutes. This stage involves further slowing of activity in the brain and body. It is much easier to be awoken during these early stages of the sleep cycle.

Stage 3

Stage 3 is the deepest part of non-REM sleep. It is also known as slow wave sleep, delta sleep and deep sleep, and can last between 20-40 minutes.

Your muscles and body relax even more, and brain waves show a clear pattern of slowed activity that is markedly different from waking brain activity. It is believed that deep sleep plays an important role in recuperation of the body as well as effective thinking and memory.

Stage 4

Stage 4 is the only stage of REM sleep. During this time, brain activity picks up significantly and most of the body except the eyes and breathing muscles experience temporary paralysis. Although dreams can happen during any stage, the most intense dreaming takes place during REM sleep.

Why is sleep important?

Sleep is as important to our health as eating, drinking and breathing. It has an important restorative function in recharging the brain at the end of each day just like we need to charge a mobile phone after prolonged use.

Physical health and development

Sleep contributes to the effective function of virtually every system of the body. It empowers the immune system, helps regulate hormones and enables muscle and tissue recovery. Lack of sleep is linked to a number of health problems including heart disease, type 2 diabetes and high blood pressure.


Sleep benefits the brain and promotes attention, memory and analytical thought. It makes our thinking sharper, recognising the most important information to consolidate learning. Sleep also facilitates expansive thinking that can spur our creativity, whether that is studying for a test or learning an instrument.

Mental health

It is no secret that there is a close relationship between sleep and mental health. Living with a mental health problem can affect how well you sleep and poor sleep can have a negative impact on your mental health and emotional wellbeing.

Sleep deprivation can leave you feeling irritable and exhausted short term, but also have serious long term health consequences as well. For example, lack of sleep has been linked to depression.

If you are having problems sleeping you might:

  • Be more likely to feel anxious and/or depressed
  • Feel lonely or isolated
  • Struggle to concentrate or make plans and decisions
  • Feel irritable or little energy to do things
  • Struggle with day to day life
  • Be more affected by other health problems

Decision making

Sleep deprivation can affect the development of the part of the brain that controls impulsive behaviour. Not getting enough sleep makes it more likely to engage in high-risk behaviours like texting while driving or riding a bike without a helmet.

Behavioural problems can then have widespread affects that harm academic performance as well as relationships with family and friends.

Development during puberty

The teenage years are a formative period. The brain and body experience significant development during this period, and the transition to adulthood brings important changes that affect a person’s emotions, personality, social and family life, and academic ability. A minimum of 8-10 hours of good sleep is recommended for young people.

Deep sleep is an important factor in the onset of puberty; it is extremely important to be sure that adolescents are getting an adequate amount of sleep time per night.

During adolescence the brain makes the hormone melatonin (the hormone that regulates the sleep cycle) later at night than the brains of children and adults do. This causes the body’s circadian rhythm (the body’s natural, internal process that regulates sleep) to reset, telling the person to fall asleep later at night and wake up later in the morning.

Find out more about puberty here.

Tips on how to sleep well

A lot of the time it’s easier said than done to make changes to your habits, especially something as ingrained as a sleep schedule, even if it isn’t doing you any favours! If you want to improve the quality of your sleep, try starting by implementing changes that feel realistic to stick to, rather than trying everything all at once. Here are a few suggestions of things you could try to improve your sleep.

  • Have a good routine: doing the same things in the same order an hour or so before bed can help you drift off to sleep and keep your sleep pattern regular and consistent. This includes the weekends! It can be tempting to have a lie in or stay up later than normal on a Saturday, but it’s a good idea to try not to sleep in for hours at weekends. Late nights and long lie-ins disrupt your body clock and make it harder to maintain a consistent and reliable sleep routine.
  • Limit screens in the bedroom: do not have a mobile, tablet, TV or computer in the bedroom at night, as the light from the screen interferes with sleep. Try to have at least an hour of screen-free time before going to sleep.
  • Exercise for better sleep: regular exercise helps you sleep more soundly, as well as improving your general health. Teenagers should be aiming for at least 60 minutes exercise every day, including activities such as walking and running.
  • Try to relax before going to bed: have a warm bath, listen to quiet music or do some gentle yoga to relax your mind and body.
  • Cut out caffeine: cut out or drink less caffeine. Caffiene is a chemical found in drinks such as cola, tea and coffee, and too much of it can stop you falling asleep and reduce the amount of deep sleep you have.
  • Avoid smoking: nicotine is a stimulant. People who smoke take longer to fall asleep, wake up more frequently and often have more disrupted sleep. Find out more about smoking.
  • Try not to eat too close to bedtime: eating too much or too little close to bedtime can lead to an overfull or empty stomach, causing discomfort during the night which may prevent sleep. Also, drinking alcohol too close to bedtime can interfere with your sleep, and drinking lots of alchohol can affect your sleep in the long term. Find out more about alcohol.
  • Create a sleep-friendly bedroom: ensure you have a relaxing sleeping environment, ideally a room that is dark, cool, quiet and comfortable. It may be worth investing in thick curtains or a blackout blind to block out early summer mornings and light evenings. Having a good quality mattress and breathable bedding will also help you sleep better, especially if you air out your bed during the day.
  • If you can’t sleep, get up: rather than tossing and turning in bed, worrying about why you can’t sleep, it’s better to get up and do something you find relaxing until you feel sleepy again, then go back to bed.
  • Write away any worries: set aside some time before bed to make plans for the next day to avoid thinking and worrying when trying to sleep.
  • Talk through any problems: talking to friends or a trusted adult like a parent or teacher can help you feel less overwhelmed by difficult things, which can help you sleep better. You will be less likely to lie awake worrying during the night if you are getting support with your mental health.

Getting help

If you have been struggling with sleep and the tips above don’t help, it is possible that you might need some more support with your sleep. If you are worried, talk to your GP about your concerns. Your GP may want to conduct a sleep study in order to get a better look at your night time sleep patterns. They can then recommend treatments that are appropriate for any underlying sleep disturbance that might be impairing your ability to rest. Treating your sleep issues early is important for protecting both your physical and mental wellbeing.

Charities, helplines and communities who can help

Find more support here.


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