Paradox of Exercise and Coronary Artery Calcification: Potential Underlying Mechanisms.

Regular exercise is widely known to exert beneficial effects on the cardiovascular system. Despite the widely accepted and numerous benefits of exercise, whether there is an upper limit to these benefits is unclear, particularly with regard to atherosclerotic disease. Observational cohort studies over the past 2 decades have identified a consistent signal of increased coronary artery calcification in older men, who have been exposed to high volumes of endurance exercise over their lifetime. The clinical ramifications of these findings are not fully known, as outcomes studies in these athletic populations are needed, but given the strong associations of coronary artery calcification with adverse cardiovascular events, a deeper mechanistic understanding of the link between endurance exercise and coronary artery calcification is needed. In this review, we describe the possible underlying mechanisms that may explain this conundrum of the athlete calcification paradox at the molecular and cellular levels.