Recent literature suggests reduced benefits associated with high intensity (HIT) and or sustained intensity exercise training (SIT). While important, they tend to contrast with other studies of HIT and SIT and may not be representative of all individuals wishing to participate in activities such as marathon running. The purpose of this observational report is to describe a 45-year history of 54 long distance runners, their incidence of death from cardiovascular disease and their ages at death compared to the normal population. Data were collected longitudinally on all 54 members of a Southern California mens running club by the author, a cardiologist with 45 years of experience, member of the running club, and personal physician for most of the men for over 40 years. Retrospective and observational data were collected from direct professional and personal contact with the 54 men in the running club. Closely monitored group of marathon runners with extreme HIT and SIT revealed a low incidence of cardiovascular disease (CVD) with an extended longevity relative to the general population. The benefits of exercise for reducing risk of chronic disease, including CVD, are well known. Whether these benefits extend to the more intense and prolonged exercise associated with marathon running is unclear. However, as evidenced in the observational data presented here, at least in some populations, years of high-intensity, prolonged exercise may not be as toxic as suggested by others. Whether this is due to self-selection or predisposition is not well understood but merits further study.