How Much Sleep Do We Need

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.

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
aged 4–12 months	12–16 hours a day (including a nap)
Aged 1–2 years	11–14 hours a day (including a nap)
Aged 3–5 years	10–13 hours a day (including a nap)
Aged 6–13 years	9–11 hours a day
Aged 14–18 years	8–10 hours a day
Aged 18–64 years	7–9 hours a day
Aged 65+ years	7–8 hours a day

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.