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.
Let’s be real here—when you’re struggling to even keep your eyes open your judgment isn’t at its peak performance.
The tendency to throw reason to the wayside has to do with a lack of impulse control induced by sleep deficiency, says Matthew P. Walker, PhD, an associate professor of psychology and neuroscience at the University of California, Berkeley. It weakens the connection between the amygdala, the part of the brain that regulates emotions, and the prefrontal cortex, the part that makes most high-level decisions for the body.
“If the amygdala is the gas pedal of your emotions, then the prefrontal cortex is the break,” Dr. Walker says. “When you are sleep-deprived, that connection between those two areas is sort of severed, and as a consequence, you become imbalanced. You become all gas pedal and no break.”