As winter approaches and thoughts turn to the dark, frigid days ahead, we may fantasize about hiding somewhere and waking with the crocuses in March. Hedgehogs, ground squirrels and bears do it—bedding down for months in musky burrows. Hibernation sounds appealing, but aside from the obvious benefits of not having to arrive at work before sunrise and dodging snow-shoveling duties, it would not be very pleasant. During hibernation, core temperature drops, systems slow and the body gradually exhausts itself—hardly a restful way to pass the season.

The human hibernation of popular culture misses this point entirely. In the Brothers Grimm version of Sleeping Beauty, the princess wakes fresh-faced and cheerful after a hundred years of slumber. Rip Van Winkle stirs from his 20-year snooze...