Why eight hours a night isn’t enough, according to a leading sleep scientist

For something that we spend a third of our lives doing (if we’re lucky), sleep is something that we know relatively little about. “Sleep is actually a relatively recent discovery,” says Daniel Gartenberg, a sleep scientist who is currently an assistant adjunct professor in biobehavioral health at Penn State. “Scientists only started looking at sleep 70 years ago.” As anyone who has lay awake at ni