Purple Band 8
WHY DO WE SLEEP?
O D Y WH ? P E E L S E W
Every night, you fall asleep. But what happens next? Find out about the strange world of sleep, why we do it, how animals sleep, and what dreams are for. Browse the complete Collins catalogue at
www.collins.co.uk
An information book
Anna Claybourne
www.collins.co.uk/collinsbigcat
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Why do we need to sleep?
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What is sleep? Every night, you fall asleep. Your body relaxes, you shut your eyes and your brain seems to switch off. Sleep is when your body rests, recovers and gets ready for the next day.
Did you know? Each person spends about one third of their life asleep. That’s 228,000 hours, 9,497 days or 26 years!
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Why do we sleep? You need sleep just as much as food, water and exercise. Firstly, sleep gives you a rest. You get a break from moving, talking, thinking and using your senses.
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While you rest, your body repairs damage, such as cuts and scrapes. You also grow more when you’re asleep! Your brain is busy too. It sorts out everything that happened during the day and stores the important things as memories. Sleep helps the things you’ve learned that day to stay in your head.
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What happens to your brain and body when you sleep? As you fall asleep, your breathing and heartbeat get slower, and your muscles relax. Then your brain starts to ignore signals from your senses. That’s why you don’t hear or feel much when you’re sleeping.
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Brainwaves Our brains work using tiny electrical signals. They happen in patterns, called brainwaves. When you’re awake and busy, your brainwaves are fast, like this.
Sleeping brainwaves are bigger and slower, like this. 7
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Purple Band 8
WHY DO WE SLEEP?
O D Y WH ? P E E L S E W
Every night, you fall asleep. But what happens next? Find out about the strange world of sleep, why we do it, how animals sleep, and what dreams are for. Browse the complete Collins catalogue at
www.collins.co.uk
An information book
Anna Claybourne
www.collins.co.uk/collinsbigcat
54784_Cover.indd 1
20/03/2021 12:13