By Melissa Deeder
Why we sleep has been a question that scientists and philosophers have been trying to find an answer to for centuries.
US scientists believe they have now found the answer; we sleep so that the brain can clean itself out.
“We need to sleep because we have a microscopic cleaning system that removes many of the toxic waste products from the brain,” said Maiken Nedergaard, M.D., D.M.Sc. in a video on the University of Rochester Medical Center website.
To conduct the study, researchers used rats and mice because they have brains comparable to the brains of humans.
They found that when rodents sleep, their brain cells shrink. This allows the cerebral spinal fluid to flow ten times faster compared to when the mice and rats were awake.
According to the study, this sleep is what flushes out the toxic waste products in the brain. The waste products then get sent to the liver where they are broken down.
According to the University of Rochester Medical Center study, the waste products include toxins that cause Alzheimer’s Disease as well as other neurological disorders/
The idea of the brain cleaning itself has been a theory for quite a long time, said Alistair W. MacLean, Professor of Psychology at Queens University.
“It’s been a hypothesis that’s been suggested for a number of years certainly by people studying sleep.”
“Just exactly how it is clearing out the brain is more a matter of contention,” he said.
MacLean tells Humber News his main theories about sleep are that, “whatever it is we do during sleep restores us in a physiological and psychological sense.”
“Sleep in a revolutionary sense is protective because we are not night adaptive animals so by sleeping we protect ourselves from wandering around and falling prey to animals,” said MacLean.
Sleep is something we need whether we know why or not
There are hundreds of studies looking at the affects of sleep loss, said MacLean.
Not getting enough sleep at night “certainly poses enough risk to us generally,” he said.
“Those affects cause psychological changes,” said MacLean. “Physiological changes and changes in performance. When we lose sleep we become more irritable and it probably affects our decision making.”
“The evidence is that sleep shows a basic biological function,” said Nedergaard in the video.
“Sleep is absolutely essential for the removal of toxic waste products.”