“Clinical and scientific research shows us that adults need 7-9 hours of sleep,” says neuroscientist Claudia Aguirre. She adds, “Studies show that even 6 hours a night have an increased link to stroke and other inflammatory events.” Why is sleep so essential for the human body? “The energy resources that the brain requires has some by product. It’s like driving a car, you burn up some fuel but the fuel inevitably leads to exhaust,” says she. “The brain, during sleep, and only sleep is when it cleans up the toxins.” Likewise, the skin has its own circadian clock and evening is prime time for repairing damage and for rebuilding cells and tissues.