4. Sleep refreshes your immune system.
The idea that sleep resets your brain and but also to the immune system, which fights infections by day but reorganizes itself and replaces dead cells by night.
The sleep-deficient human brain actually mirrors that of a person with an actual psychological disorder when faced with negative situations, according to a study published in the Journal of Neuroscience.
“It’s almost as if the brain was having a disproportionately increase or an exaggerated response to something bad when you’re sleep deprived,” says Dr. Walker.
During deep REM sleep, the brain is able to “reset those emotional settings” and refresh the mind, similar to how one might reboot a computer when it’s acting up. Your brain needs that downtime to digest all the emotions from the previous day.