According to a new study, a good night's sleep may literally help to clear your brain and refresh your mind.
Research in mice has shown that the space between brain cells increases during sleep, allowing toxins that build up during waking hours to be flushed out.
These findings have enormous implications for the effects of sleep on health and disease.
For centuries, scientists and philosophers have wondered why people sleep and how sleep affects the brain. This new and exciting study now shows that sleep may be necessary for the brain to cleanse itself of toxins.
How does this happen?
It seems a plumbing system called the glymphatic system opens up during sleep - this system has previously been shown to control the flow of cerebrospinal fluid (CSF), a clear liquid surrounding the brain and spinal cord.
The study authors studied how the glymphatic system behaves during sleep by injecting dye into the CSF of mice and watching it flow through their brains. To their surprise, the dye flowed rapidly when the mice were unconscious, either asleep or anesthetized.
On the other hand, the dye barely flowed when the same mice were awake.
These results suggested that the space between brain cells changes greatly between our conscious and unconscious states. And in fact the researchers found, by direct measurement, that the space inside mouse brains increased by 60 percent when the mice were asleep or anesthetized.
Previous studies had shown that toxins implicated in neurodegenerative disorders tend to accumulate in the space between brain cells.
In this study, the researchers injected mice with labeled beta-amyloid, a protein associated with Alzheimer's disease. They measured how long it stayed in their brains when they were asleep or awake.
Intriguingly, beta-amyloid disappeared faster from mice brains when they were asleep - once again reinforcing the idea that sleep helps to clear toxins from the brain.
These results have broad implications for the treatment of neurological disorders. For instance, in future cells regulating the glymphatic system may become new targets for treating such disorders.
In the meantime, it’s clear that sleep is very important for your brain to recover from the stress of its daily activities.
Are you getting your 7 or 8 hours of sleep daily?