Emily Manoogian, PhD, has made a career out of asking when. Manoogian is a chronobiologist—a fancy word for someone who studies circadian rhythms. As we go about our daily lives, sleeping, eating, exercising, and more, our bodies respond by tuning internal biological clocks. Our habits can make or break these clocks, and Manoogian is finding out exactly what and when those habits are so we can optimize our circadian rhythms for long-term health.