A messed-up body clock could be a bigger problem than lack of sleep

On the eve of Daylight Saving Time, I flew home to Vermont from California. Crossing several time zones, I arrived near midnight. At 2 a.m., the clock jumped ahead an hour, leaving me discombobulated.

“How messed up am I?” I asked sleep researcher and evolutionary anthropologist David Samson days later. Jet lag can make people feel moody and hungry at weird times, but my extreme state probably masked chronic sleep dysregulation, he told me.

For most of human history,…