If we are born to walk and run, why do most of us take it easy whenever possible? Does running ruin your knees? Should we do weights, cardio, or high-intensity training? Is sitting really the new smoking? Can you lose weight by walking? And how do we make sense of the conflicting, anxiety-inducing information about rest, physical activity, and exercise with which we are bombarded? In this myth-busting book, Daniel Lieberman, professor of human evolutionary biology at Harvard University and a pioneering researcher on the evolution of human physical activity, tells the story of how we never evolved to exerciseto do voluntary physical activity for the sake of health. Using his own research and experiences throughout the world, Lieberman recounts without jargon how and why humans evolved to walk, run, dig, and do other necessary and rewarding physical activities while avoiding needless exertion. Exercised is entertaining and enlightening but also constructive. As our increasingly sedentary lifestyles have contributed to skyrocketing rates of obesity and diseases such as diabetes, Lieberman audaciously argues that to become more active we need to do more than medicalize and commodify exercise. Drawing on insights from evolutionary biology and anthropology, Lieberman suggests how we can make exercise more enjoyable, rather than shaming and blaming people for avoiding it. He also tackles the question of whether you can exercise too much, even as he explains why exercise can reduce our vulnerability to the diseases mostly likely to make us sick and kill us.