If we are born to walk and run, why do most of us take it easy whenever possible? And how do we make sense of all the conflicting, confusing, anxiety-provoking information about rest, physical activity and exercise?

Professor Daniel Lieberman, Human Evolutionary Biologist at Harvard University has written a new book entitled Exercised: Why Something We Never Evolved to Do Is Healthy and Rewarding. The notion of exercise is modern, weird, and unpleasant, so the best way to do more is to find something you enjoy.