Waking up is hard enough. Waking up at the exact same time every day—even on weekends, when you could be luxuriating for another hour (or three) under the covers—can feel borderline unreasonable. Yet ...

Time rules life, and body clocks direct and define much of yours. 24 hour (circadian) clocks continue to be implicated in most aspects of human health, joy, and performance. A recent British study out ...