-- Why We Sleep Anyone having trouble sleeping has heard all the old 'sleep hygiene' rules: Don't drink caffeine after 2:00 p.m., use the bedroom only for sleeping, put down your screens an hour before going to bed. But as the millions suffering from poor sleep can attest, just following these overly simplistic, one-size-fits-all directives doesn't work. How to Sleep Dr. Rafael Pelayo, an expert sleep clinician and professor at the world-renowned Sleep Medicine Clinic at Stanford University, offers a holistic approach to the myriad issues that might be affecting your sleep. He begins by grounding us in the biology of sleep including the extremely reassuring fact that no one actually sleeps through the night'we naturally wake up every ninety minutes. Dr. Pelayo then tackles the major sleep issues one by one, such as snoring and its causes; the difference between transient and chronic insomnia, and how to treat each; strategies to combat jet lag; how lifestyle choices affect your sleep, including exercise (even ten minutes helps), meditation (try it right before bed), and food and drink (alcohol is a double-edged sword'it may help you fall asleep faster, but it often interferes with staying asleep). There's advice for the bedroom'on white noise machines, ambient temperature, what to look for in a pillow'and answers to our most pressing questions, from when to see a sleep medicine specialist to how aging affects our sleep. All in all, it's a sure prescription to help you sleep better, wake up refreshed, and live a healthier life.