“Humans really are obligatorily required to do aerobic exercise in order to stay healthy, and I think that has deep roots in our evolutionary history,” Dr. Lieberman said. “If there’s any magic bullet to make human beings healthy, it’s to run.”

Real-time tracking also shows that people are happier during moments when they are physically active than when they are sedentary. And on days when people are more active than their usual, they report greater satisfaction with their lives.