It used to be cool to eschew sleep. ‘I’ll sleep when I’m dead’ and ‘sleep is for losers’ were phrases that people actually once said to each other; probably while trying to emulate the rumored 4-hours-per-night sleep habits of Martha Stewart and that lazy so-and-so Tom Ford, who snoozes in his self-designed sheets for an indulgent three hours every night.

By and large, the sea of change has happened (probably while we were sleeping), and many of us now value sleep a lot more.

How We Learned to Love Sleeping

It’s no longer just that thing we do when we’re not being awake: our entire physiology depends on …