Sleep plays an essential role in your health and wellbeing throughout your life. Getting enough good quality sleep has many benefits, including protecting your physical and mental health, quality of life and personal safety.
Key points
- When you sleep, important physical and mental processes are carried out.
- Regular, good quality sleep is important for brain functioning, emotional wellbeing, physical health, daytime performance and personal safety.
- Research suggests that adults need at least 7 to 8 hours of sleep each night to be well rested.
- Not getting enough sleep is common and can have serious impacts on your health and wellbeing.
- To restore your sleep balance, you need at least two nights in a row of unrestricted good quality sleep.
What happens when we sleep?
When we sleep, our bodies rest – conserving energy and decreasing blood pressure, heart rate, breathing and body temperature. At the same time, our brains remain active – laying down memory, restoring daytime mental functioning and carrying out processes that lead to physical growth.
There are five stages of sleep, progressing from stage 1 (light sleep) through stages 3 and 4 (deep sleep) to stage 5 known as rapid eye movement (REM) sleep. Read about what happens during these different stages of sleep
Sleep is thought to play an important role in the following processes:
- Controlling your body temperature and energy use (metabolism).
- Keeping your immune system working.
- Controlling your brain functioning and restoring your memory.
- Keeping your heart and blood vessels healthy.
- Repairing tissues and stimulating growth in children (growth hormone released during sleep is responsible for both).
- Regulating your appetite and weight and controlling your blood glucose levels.
If you aren’t getting enough sleep on a regular basis, these processes are interrupted and your risk of developing long-term health problems increases.
How much sleep is enough?
The type and duration of sleep you have changes during your lifetime. How much sleep you need also varies from person to person but the following table provides a general guide.
|
Age |
Recommended amount of sleep |
|---|---|
|
Infants aged 4–12 months |
12–16 hours a day (including naps) |
|
Children aged 1–2 years |
11–14 hours a day (including naps) |
|
Children aged 3–5 years |
10–13 hours a day (including naps) |
|
Children aged 6–13 years |
9–11 hours a day |
|
Teens aged 14–18 years |
8–10 hours a day |
|
Adults aged 18–64 years |
7–9 hours a day |
|
Adults aged 65+ years |
7–8 hours a day |
|
Source: National Sleep Foundation US, 2015 |
|
What happens if we don’t get enough sleep?
If you regularly aren’t getting enough sleep, your sleep loss adds up. The total sleep lost is called your sleep debt. For example, if you lose 2 hours of sleep each night, you'll have a sleep debt of 14 hours after a week.
The harm caused by not getting enough sleep can be immediate, such as in having an accident due to not being able to focus and respond quickly. Other effects can take years to develop, such as an increased risk of developing a chronic health problem.
Lack of good sleep can lead to:
- excessive daytime sleepiness, tiredness and lethargy
- morning headaches
- poor memory and difficulty focusing
- anxiety and depression
- chronic health problems such as obesity, diabetes and cardiovascular disease
- an increased risk of alcohol and drug dependence
- having a car accident
- making mistakes at work, including causing accidents
- relationship problems
- lack of sex drive.
In young people, lack of quality sleep may have a direct effect on their health, development, behaviour and ability to socialise and get along with their peers.
How to counter sleep debt
Getting enough sleep can be likened to banking your savings: if you take sleep out of your account, you have to put it back in to restore the balance – there’s no other way to catch up. Lack of sleep night after night leads to sleep debt, where your performance and sleepiness both get progressively worse.
When this happens your attention, learning and physical performance all suffer. To restore your sleep balance, you need at least two nights in a row of unrestricted good quality sleep.
See sleep tips for ideas on how to improve your chances of a good night’s sleep.
Learn more
How much sleep do we really need? National Sleep Association, US, 2015
Why lack of sleep is bad for your health NHS Choices, UK
References
- National Sleep Foundation’s sleep time duration recommendations: methodology and results summary Hirshkowitz, Max et al Sleep Health: Journal of the National Sleep Foundation, Volume 1, Issue 1, 40–43