There’s no question that regular exercise is essential to health. Our paleolithic ancestors had a different word for exercise: life. For the vast majority of our evolutionary history, humans had to exert ourselves – often quite strenuously – to get food. We naturally spent a lot of time outdoors in the sun, walking, hunting, gathering, and performing various other physically-oriented tasks. We had no concept of this as “exercise” or “working out”. It was just life.