We’re kinda obsessed with sleep. In our youth, we tried to outrun it, pushing bedtimes and pulling all-nighters just because. Later, we chased it, running on empty, to no avail. No translation is needed for dark circles after a night of tossing and turning, or the glow of a well-rested face. Sleep, like breath, is universal. It’s consumed the minds of civilizations long before us. Just look at the stories: Joseph interpreted dreams in the Book of Genesis; Hypnos the Greek god of sleep put Zeus to bed; Sleeping Beauty…slept; and even Goldilocks seemed to be a bit of insomniac seeking the perfect night’s rest.
Even though sleep is a constant, the way you might think of bedtime today is probably quite different from how your grandparents thought of it, or even the generation before or after you. In fact, it wasn’t until the last hundred years or so that the eight-hour sleep cycle became the norm. In Roger Ekirch’s At Day's Close: Night in Times Past, the scholar explores the history of nighttime in Western society. We used to be all about biphasic—or two-phase—sleep, where we’d rest for a couple hours at night, wake for a few, then sleep again, but by the 19th century, historic mentions of the practice phased out in the name of efficiency and progress. The Industrial Revolution made us acutely aware of how many productive hours we had in a day. Electricity also meant that we could extend the day well past darkness, creating the cadences of life we know today.