Evidence suggests that men with high physical activity have higher levels of coronary artery calcification (CAC), but very little data is available on whether these men should continue to exercise and whether they have a higher risk of mortality. A recent study published in JAMA Cardiology by Dr. Laura F. DeFina and her colleagues from the Cooper Institute in Dallas, answers the important questions of whether extreme physical activity is injurious to health and if there is an association between increased CAC and clinical events. In short, their answer was no.
The investigators, in this prospective observational study, evaluated physical activity levels and CAC scores in 21758 individuals without any known cardiovascular disease (CVD) and followed them for around 10.4 years between 1993 to 2013 for mortality. Intense exercise was defined as 5-6 hours of vigorous activity per week. It was found that men with such high levels of physical activity had an 11% greater chance of having slightly higher CAC scores when compared to those with lower levels of exercise. Still, even in those with very high levels of CAC (mean score, >800 AU), higher levels of physical activity were associated with safety and a lower risk of cardiovascular and all-cause mortality. In this study, only 26 deaths were seen due to all causes and only 8 were due to CVD.
“Our study shows convincingly that individuals performing high volumes of exercise do not have increased all cause or cardiovascular mortality compared to individuals performing lesser amounts of exercise.”– Dr. Benjamin Levine M.D.
In an editorial published by Dr. Aaron L. Baggish M.D. and Dr. Benjamin D. Levine, recent studies on CAC and endurance athletes were discussed. They believed that “The hemodynamic and mechanical factors inherent in endurance exercise may lead to arterial wall injury and recovery calcification, this hypothesis remains speculative. If it were this simple, one would expect CAC to be present in all or at least the vast majority of endurance athlete participants. Because this was not the case, we are left to consider what factors differentiate those athletes that calcify from those that do not”. Even though aging endurance athletes may bear significant high amounts of CAC, the exact pathogenesis remains uncertain. In all, high CAC scores at any given level of physical activity can be considered as an indicator of risk assessment.
Even though high-volume physical exercise may promote calcification of coronary atherosclerosis, it is not prudent to hypothesize that decreasing physical activity would help decrease the chances or prevent cardiovascular mortality. Senior author Dr. Levine M.D. (UT Southwestern Medical Center, Dallas) urged, “I hope that cardiologists will not tell their athletes who are found to have high CAC values to reduce their exercise dose.”. He stated, “Our study shows convincingly that individuals performing high volumes of exercise do not have increased all-cause or cardiovascular mortality compared to individuals performing lesser amounts of exercise.”