By the time you reach 80, you will probably have spent about 28 of those years asleep. Good sleep is vital for your health, but it can be hard to get when life is busy, and sleeping problems are common.
Fortunately, there are many things you can do to improve your sleep.
What is sleep?
When you are asleep, your eyes are closed, most of your muscles are relaxed, and your consciousness is practically suspended. But while your body is still, your brain is quite active.
Why is sleep important?
Scientists don’t fully understand why we need so much sleep, but it’s believed it helps us restore ourselves physically, as well as organise things in our brain. You need sleep so your body and mind can function properly.
Sleep is thought to help keep your immune system strong and your heart and blood vessels healthy. It allows for growth and healing. It helps control your appetite and your weight. It’s also needed for attention, memory and learning.
Going without enough sleep can seriously affect your health. As well as affecting your concentration and mood, lack of sleep has also been linked to a range of physical problems, such as heart disease, high blood pressure, diabetes and even premature death.
People who don’t sleep enough are also more likely than others to have road accidents, and there are problems with productivity and safety in the workplace.
Common sleep problems include insomnia, snoring, and sleep apnoea (a breathing abnormality). Sleep problems can and do affect your health and safety, so if you’re feeling sleep deprived, see your doctor for advice.
Stages of sleep
Sleep has 2 main phases: rapid eye movement (REM) sleep and non-rapid eye movement (non-REM) sleep.
When you are in non-REM sleep, you go through 4 stages. During stage 1, you are in transition between being awake and asleep, and wake easily. During stages 2, 3 and 4, your eye movements stops, your body temperature falls, and you are deeply asleep.
In REM sleep, your eyes move rapidly, your blood pressure and heart rate go up, and your brain becomes very active. REM sleep is when most dreaming happens, and is thought to be important for learning and creating new memories.
REM sleep happens about every 90 minutes during the night. Adults usually spend about one fifth of the night in REM sleep and the remaining 4 fifths in non-REM sleep. Infants spend at least half of the time they’re asleep in REM sleep.
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Last reviewed: August 2018