REAL LIFE NEWS: WHY DO WE SLEEP?
by Hazed
I seem to be writing a lot about sleep. In recent issues I’ve told you that having a lie-in is good for you, and that staying in bed too long is bad for you. It’s beginning to sound like I am obsessed with the subject – but it’s not me, honest, it’s just that lots of stories crop up in the newspapers.
Now this week we get a theory about why sleep is so important. Scientists still don’t really know why we sleep – they have figured out that bad things happen if we don’t get enough sleep, but that’s not the same thing. Sleep leaves animals in danger of predators so if they have evolved to spend large chunks of their time asleep despite this, it must be for a pretty good reason. What could that be?
Well, now they think that the reason – or at least one of the reasons – is that sleep allows the waste toxins that build up in the brain during the day to be washed away.
A new study shows that during sleep the brain cells shrink. This opens up gaps between the neurons and allows fluid to wash the brain clean. This builds on a discovery last year in which it was found that the brain had a network of pipes, called the glymphatic system, which carries the waste material away.
The scientists imaged the brains of mice and showed that this plumbing system is ten times more active during sleep than when the rodents were awake. This pumping action is probably not compatible with being awake and thinking, so sleep turns information processing off allowing the housekeeping to take place.
“The brain only has limited energy at its disposal and it appears that it must choose between two different functional states – awake and aware or asleep and cleaning up,” said researcher Dr Maiken Nedergaard.
“You can think of it like having a house party. You can either entertain the guests or clean up the house, but you can’t really do both at the same time.”
Similar experiments would need to be done on humans to find out whether the same is true for us as it is for mice. If it does turn out to apply to us as well it could have implications for diseases such as Alzheimer’s or Parkinson’s in which the brain suffers a build-up of damaged proteins.
Source: http://www.bbc.co.uk/news/health-24567412
Bonus link: the Onion tells us that human beings were never meant to wake up from sleep: http://www.theonion.com/articles/new-study-finds-human-beings-were-never-meant-to-w,34288/. Sounds plausible to me!
