October 21, 2013
More To Sleep Than Resting
I have read a couple of interesting articles recently about what goes on when we sleep, both on the BBC. One about how sleep is important for storing memory, among other things, and another about how sleep helps to spring clean the brain.
One slightly confusing thing that came up in the articles was the suggestion that until now we didn’t really know why we slept, and that it confuses scientists why some animals would sleep at all when it makes them so vulnerable to predators. Isn’t the answer ‘to rest, and restore energy levels which have been depleted during the day’? Apparently not; there is much more to sleeping than that.
The cleaning thing is related to toxins that build up during the day as a result of thinking, stress, and other grafting that the brain does. These are flushed out during sleep, when, according to a study in the US journal Science, brain cells actually shrink in order to open up space between neurons, leaving room for fluid to ‘wash’ the brain.
Researcher Dr. Maiken Nedergaard from the University of Rochester Medical Center said that it helps to think of the brain’s need to do chores at night after its daytime work as “…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.” Cleaning the brain takes a lot of energy, and can’t be done at the same time as all the things that it has to process when we are awake.
The idea that deficiencies in the cleaning process could be a possible cause of conditions such as Alzheimer’s or Parkinson’s disease is a theory which needs more work, but a promising one nevertheless. Either way, it’s worth hedging our bets and getting more sleep to help the procedure.
The other article concerned with sleep suggested that getting a bit of extra shuteye would help in different ways too. The idea seems fairly obvious, but then there has been a slight trend recently to question the widely held belief in the 8-hour sleep cycle. The answer is probably that us all needing exactly 8 hours sleep is unlikely, but whatever our personal average range is, be it 4-6 hours or 7-9 hours, we should aim for the top end of the spectrum and try to keep the average pretty stable. If it’s possible to get 7 hours plus then, that is highly desirable.
So, what are the other advantages of a bit more sleep? Retaining memory is one. During deep sleep, short-term memories are moved to long term and this can only be done within 24 hours of getting the memory. If we don’t have enough deep sleep some memories will be lost.
In terms of health, researchers at University of Surrey Sleep Research Center in the UK found that the activity of genes during sleep is a factor, when comparing one group who got six and a half hours’ sleep during the experiment with another group who got seven and a half. In the group that got less sleep, genes related to things such inflammation; immune response and response to stress were more active. There was also more activity in genes connected with diabetes and risk of cancer. In the group that had more sleep, this undesirable gene activity was reduced.
So, I have been put in my place. There is much more going on during sleep than simply resting and dreaming, and much more to think about, when we decide how much sleep we should have, than just feeling tired the next day.
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