When I was a medical student and resident, sleep was considered optional. Delivering 500 babies and working in the emergency department for overnight shifts fried my nervous system. I learned firsthand the dangers of sleep deprivation. Sleep, while it may seem superfluous, is essential to our health and longevity. The notion of “I’ll sleep when I’m dead” may cause you an early death. It affects every aspect of our health, including our metabolism, weight, mood, and cognitive function.