As Daniel Lieberman explains, “If you want to understand the human body, you have to understand that we evolved to be hunter-gatherers. That means being prepared to expend a lot of energy to acquire food, but not wasting energy when you don’t need to.” So exercise is important, but rest is vital, too. “For one thing,” Lieberman says, “you can’t digest food while you are exercising because the body shunts blood away from the digestive system in order to meet the increased demand to supply oxygen to the muscles. So you have to rest sometimes just for metabolic purposes and to recover from the
...more
