I was always an early riser, but having to be at the hospital by 5 or so AM refined that predisposition. A new study of sleep shows that when we go to bed, how long it takes to fall asleep, and countless other measures of our biological need to sleep are part genetic and part cultural.
social jetlag
Biologically, we live on the clock, driven by a neurochemical in our brains responsible for circadian rhythms. That tick-tock controls our sleep and wakefulness; the release of hormones; feeding; metabolism; even our immune system. When the rhythm of signaling is disrupted, our health can suffer. Those issues have been in the news as we recently transitioned to Daylight Saving Time. They also may have factored into the U.S. Senate voting unanimously to make DST permanent. Here we separate science fact, from science fiction.