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.
Your body’s internal systems control when you sleep and when you’re awake. If these systems get out of alignment, such as due to shift work or jet lag, sleep problems can result.
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.
Sleep and your health
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.
Last reviewed: November 2016