Facts about Sleep



Sleep need varies


Sleep is an active state

We used to think that everything shuts down when we sleep.  But over the last 60 years scientists have discovered that our brains are very active while we sleep.  In fact, some parts of the brain use more oxygen and glucose while asleep than when awake.

Deep sleep happens first


Sleep changes in cycles


A body clock affects our tiredness


Falling asleep can be hard


Lack of sleep can bring you down

Some people cope with a lack of sleep much better than others.  But everyone who is very sleepy loses concentration easily and experiences mood changes.   The usual mood changes are feeling more depressed and irritable.

Genetics and sleep

We now believe that many aspects of sleep are genetically controlled.  Recent breakthroughs may have identified the gene that makes some people cope more easily with a lack of sleep.

Why do we sleep?

Scientists don’t yet understand exactly why we need sleep so badly.  They believe it restores us physically and helps us organise things in our brain. We do know, however, that we can’t live well without it.