• Question: Which are the main difference between being fainted and sleeping?

    Asked by anon-189159 to Michael, Rachel on 5 Nov 2018. This question was also asked by anon-189085.
    • Photo: Mike Ambler

      Mike Ambler answered on 5 Nov 2018:

      Hi Paulito, thanks that’s an interesting question!

      Fainting is a strange process: your brain tells your blood vessels to relax, which means that less blood comes back round your body to the heart, your brain also tells your heart to slow right down.. the result is that not enough blood is pumped out of your heart and up to your brain. Without enough blood your brain can’t work properly so you become unconscious and fall to the ground.

      Sleep isn’t quite the same, although you are not conscious in both situations, sleep doesn’t involve reduced blood flow to the brain. It is not clear what the purpose of fainting really is to be honest, but sleep involves lots of useful things like repairing the body and sorting out memories from the day.

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