In college, Olivia Walch was a self-described "sleep deprivation cowboy." She would go days with only 3 to 4 hours of sleep and then binge sleep at other times. But soon, it all caught up with her. Now, she's a sleep researcher at the University of Michigan with a simple message: Sleep regularity is key — as is darkness. She joins host Maiken Scott to discuss her new book "Sleep Groove: Why Your Body's Clock Is So Messed Up And What to Do About It."