The Primal Blueprint 21-Day Challenge manifests differently for everyone. Some folks are focused on improving their diets, on removing this food or adding that food. Some have committed to optimizing their sleep by getting to bed at a certain time and eliminating nighttime electronics. And many just want to look better naked. But there’s one tie that binds nearly everyone I’ve interacted with through the course of this and previous challenges: physical activity. Whether you’re trying to eat, sleep, or look better, exercise matters. Effective exercise especially matters for everyone, and my intent when creating Primal Blueprint Fitness was to democratize fitness without compromising it—to distill effective training down to its essential elements so that everyone could practice it.