The overall health benefits of physical activity have been known for several decades. It is clear that consistent participation in physical activity leads to large physiologic adaptations that are closely connected to improved cardiorespiratory, vascular, musculoskeletal, mental, and metabolic health. These effects are pervasive across the lifespan. In fact, there is no single medication treatment that can influence as many organ systems in a positive manner as can physical activity. These findings have led several health organizations to publish guidelines for the conduct of a recommended amount and intensity of physical activity (eg, American Heart Association, The Obesity Society). These various recommendations culminated in 2008 when the US Department of Health and Human Services published the first Physical Activity Guidelines for Americans (http://www.health.gov/paguidelines/guidelines/). The guidelines state that “…some physical activity is better than none, and adults who participate in any amount of physical activity gain some health benefits”1(p7) and that “For substantial health benefits, adults should do at least 150 minutes (2 hours and 30 minutes) a week of moderate-intensity, or 75 minutes (1 hour and 15 minutes) a week of vigorous-intensity aerobic physical activity….”1(p7) Adults should perform aerobic activity in bouts of at least 10 minutes spread throughout the week. The recommendations state that although there have been a few reports of heart complications due to very high levels of activity, additional health benefits can be gained with higher doses of physical activity beyond the recommended amount.