Question: why do we sleep for like 8 hours a night ?

Alex Reid answered on 7 Nov 2018: last edited 7 Nov 2018 5:07 pm

Hi and thank you for your great question. It is true that your average adult benefits the most from around 8 hours of sleep a night, but this number comes with two really important extra pieces of information I need to tell you about. Firstly, that number doesn’t fully tell us how much variation there is in the amount of sleep people need. A better way of saying it is that most people need 8 hours of sleep plus or minus two hours, that is quite a range! (6-10 hours!). So while it is true to say the average amount needed is 8 I don’t think people should get too fixated on getting this number exactly because it really comes down to what you need as an individual. Secondly, the amount of sleep you need will change as you go through life. Notice I said ‘adult’ above when talking about 8 hours. As a child you will probably need more sleep than this, and as a baby you would have probably needed even more! By that same token your grandparents will not need as much sleep as you or your parents. While this is all interesting it doesn’t really answer what you were really asking us though: why do we need sleep? Although I am a psychologist who looks at memory I am always aware sleep does lots of different things. It helps you heal and grow faster, and provides other important biological processes that generally keep you alive. As a young person you have a lot of growing to do, and there is a lot about the world your brain is wanting to learn, this is why you need sleep. The duration of your sleep (whatever that may be) is the length of time you will need as an individual to help you properly do all of the above (heal, grow, learn and live).