• Question: why do we sleep?

    Asked by to Nick, Anna, Chris, Jane, Iain on 18 Mar 2014. This question was also asked by .
    • Photo: Anna Middleton

      Anna Middleton answered on 18 Mar 2014:

      Hi cookie555 we sleep because we can’t function if we don’t. Sleep is really important time for the brain to reset itself and for subconscious and conscious thinking to filter what is going on.

      We seem to need a lot of sleep when we are teenagers as the brain is going through a lot of change then. This settles down in your 20s and then as we get older we seem to need less sleep.

    • Photo: Jane Charlesworth

      Jane Charlesworth answered on 18 Mar 2014:

      I don’t think we know for sure why we sleep. I thought it was so our bodies could save energy and recover from the day, but when I looked it up, it turns out we only save about 50 kcal of energy in 8 hours of sleep, which is about the same as a piece of toast! Another idea, which sounds more believable for me, is that our brain cells clean themselves while we sleep–according to this theory, our brains wash themselves with spinal fluid, which filters out nasty chemicals that built up during the day and takes them to our livers.

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