• Question: why do we sleep

    Asked by Hassan to Chris, Josh, Rebecca, Rob, Susan on 16 Jun 2015. This question was also asked by #nerdyweirdo.
    • Photo: Rebecca Dewey

      Rebecca Dewey answered on 16 Jun 2015:

      We don’t know the full explanation for this. There are a number of reasons why sleep is beneficial – it allows the body to heal and to boost the immune system and let organs function, catching up on processes from the day and getting back into top shape. Also, dreaming is very good for you mentally, to allow the brain to process all the things that are subconsciously going round. But we don’t know *why* we sleep. Other than the fact that removing the need for sleep (in experiments with mice, rats etc) doesn’t go very well!

      There’s still a lot of research going on into sleep – I recently volunteered for a friend’s research when I had to try and sleep in a brain scanner so that they could watch what my brain activity did. I don’t yet know what they found, but it’s all really exciting!

    • Photo: Susan Cartwright

      Susan Cartwright answered on 16 Jun 2015:

      I am not a biologist, and certainly not a sleep specialist, but as far as I know we do not know the answer to this. We know sleep is necessary – experiments in which volunteers have been deliberately deprived of sleep show that their mental functioning deteriorates sharply, and there is a very rare genetic disease called Fatal Familial Insomnia which prevents the sufferer from sleeping at all, with, as the name indicates, lethal results – but we don’t know why it’s necessary.

      As far as I know, all animals sleep, but some, such as dolphins, sleep with only half of their brain at any given time. This is because dolphins have to be awake in order to surface to breathe, so one half of the brain stays awake (though not very alert) to manage this – then the two halves switch over. Swifts sleep while flying, and apparently have independently evolved the same trick. The fact that these animals have developed special tricks so that they can sleep, even though it is not to their advantage to do so, strongly indicates that sleep is absolutely vital – but we still don’t know why.

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