• Question: Why do creatures need to sleep? e.g. Us, humans, or dogs?

    Asked by silverfox to Charlie, Eoin, Jemma, Julian, Steve on 18 Mar 2011.
    • Photo: Charlie Ryan

      Charlie Ryan answered on 16 Mar 2011:

      Hi silverfox didn’t you ask a question on dreaming aswell???!
      I’m sorry i don’t know – it is a bit funny though thinking about it. We sleep a third of our lives!! And i have no idea why!!

    • Photo: Stephen Moss

      Stephen Moss answered on 17 Mar 2011:

      Hi Silverfox

      This is a great question, and one that lacks a really clear answer. One reason seems to have something to do with ‘consolidating memories’ – in that when we sleep, the brain hardwires recent memories (maybe the things you’ve done that day) so that we recall them much better in the future. But there are other reasons too, possibly to do with rebalancing chemical signals in the brain. It’s a difficult subject to study experimentally, so it could be a long time before we fully understand the need to sleep.

    • Photo: Jemma Ransom

      Jemma Ransom answered on 17 Mar 2011:

      The short answer to your question is we simply don’t know. Sleep is clearly vital for most animals, take for instance the flamingo – they rest each side of their brains individually, so when the right side of the brain is asleep, the left is awake. If you’ve ever seen a flamingo at a zoo standing on one leg, this is because the side of the brain controlling the leg in the air is asleep – Some scientists think that the brain needs sleep so it has time to make chemicals called neurotransmitters, these are molecules that carry signals between brain cells. It has also been suggested that babies sleep so they can process the information they have gathered through their senses during the day. These are all theories, but there is very little evidence to support one over another.

    • Photo: Julian Rayner

      Julian Rayner answered on 17 Mar 2011:

      Hi sliverfox. I honestly don’t know the answer. However, I understand that our brains need periods of rest to process all the information it receives during the day. Think about how many sights/sounds/smells you take in during a day at school, let alone the ideas that you learn. Your brain needs down time to file that stuff, work out what it wants to keep and what it wants to throw away, etc, and all that happens while you sleep.

      Think of it like a computer without a cooling fan. It could run for a while just fine, but then it would overheat and fry. If you ran it for a while and then switched it off to let it cool down, it would work much better…

    • Photo: Eoin Lettice

      Eoin Lettice answered on 18 Mar 2011:

      Hi silverfox,
      Another great question! This is another one of these mysteries that is difficult to solve!
      It certainly isn’t to save energy – we use lots of energy when we’re asleep as well as when we are awake.
      If we don’t sleep though, we know all about it – our ability to do simple tasks, like talk and drive and read becomes reduced. That’s why it is very dangerous for drivers to continue to drive when they are sleepy.
      So, my guess is that it is all about giving your brain a break! But it’s a complicated question and maybe other people have different ideas of why we sleep!

      Eoin

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