Scott Johnston is joined by Doctor Jesse Charles, M.D. Jesse is a rural medical doctor and longtime adherent to the Uphill Athlete training methods. As a general practitioner in a rural setting, Jesse sees a wide variety of patients, from those at peak health, to the infirm. In this episode, Scott and Jesse discuss changes that take place as the result of regular exercise; exercise as a ‘phase change’ in the functioning of the body; how exercise facilitates learning; responses of the heart to exercise; nervous system changes and loss of motor units through time; the importance of balance practices in aging populations; the evolution of mitochondria; gut bacteria as a health indicator throughout life; dietary considerations for gut health; training progressions and adaptations for increasing vitality; and thoughts on arthritis prevention.