There is no denying the benefits of regular exercise on your cardiovascular health. Physical Activity Guidelines indicate that 150 minutes of moderately vigorous exercise per week can decrease risks for fatal and non-fatal cardiovascular disease 1. Although there is more concern regarding low levels of activity and the negative impact it can have on your health given that if affects more of the American population, there has been increasing interest in the effects of high endurance exercise on the cardiovascular system. Recently, a few small studies have been published linking high levels of endurance activity that are well beyond the recommended amount, to development of atherosclerosis 2. However, there has been little research on, and even fewer guideline recommendations for, patients who engage in very high levels of physical activity who have clinically significant coronary artery calcification (CAC) and the long-term effects that may have on overall mortality. A new study published in the Journal of the American Medical Association (JAMA Cardiology) on January 30, 2019 addressed just that.
This study involved 21,758 men with a mean age of 51.7 years old who were patients at the Cooper Clinic, a preventative medicine clinic that focuses on lifestyle modification, in Dallas, TX from 1998 to 2013. All participants reported their level of physical activity via a questionnaire and underwent CAC scanning, and had follow ups through 2014. The study ended up with 3 groups based on the answers they received from the questionnaire regarding the participants activity level; >3000 metabolic equivalent tasks (MET-min) of exercise per week, 1500-2999 MET-min, and <1500 MET-min. The most active group, >3000 MET-min, indicated that they were involved in greater than 5 hours of vigorous exercise per week, which is equivalent to running 6 miles per day at a 10 minute pace.
What they found was that men in the most active exercise group were more likely to have clinically significant CAC when compared to the less active groups in the study. Interestingly, despite this group having higher levels of CAC, this study found no increased risk of mortality when compared to their less active counterparts and in fact showed that this group had lower risk of mortality when compared to the less active groups 3.
How could this be? One theory is that the calcifications formed in this vigorous activity group are more stable than the soft, non-calcified plaques that are more often the cause of heart attacks and strokes 4. So despite the findings that these high endurance participants have higher rates of CAC formation, the study concludes that there is no increased in mortality in this group and they can continue to exercise safely without much concern. Dr. Carl Lavie of the John Ochsner Heart and Vascular Institute in New Orleans, LA provided commentary on this research article, stating that though the study found better outcomes for the high intensity exercise group with clinically significant CAC, that should not preclude them from being treated with lipid lowering therapies such as statins 4.
1. Committee PAGA. Physical Activity Guidelines Advisory Committee Report, 2008. Washington, DC: Dept of Health and Human Services; 2008.
2. Baggish AL, Levine BD. Coronary artery calcification among endurance athletes: “Hearts of Stone”. Circulation. 2017;136(2):149-151. doi:10.1161/ CIRCULATIONAHA.117.028750
3. DeFina LF, Radford NB, Barlow CE, et al. Association of All-Cause and Cardiovascular Mortality With High Levels of Physical Activity and Concurrent Coronary Artery Calcification. JAMA Cardiol. Published online January 30, 2019. doi:10.1001/jamacardio.2018.4628
4. Lavie CJ, Wisløff U, Blumenthal RS. Extreme Physical Activity and Coronary Artery Calcification—Running Heavily and Safely With “Hearts of Stone”. JAMA Cardiol. Published online January 30, 2019. doi:10.1001/jamacardio.2018.4647
5. Lou N. Heavy Workouts Linked to Hard Arteries. Medpage Today. Published online January 30, 2019. https://www.medpagetoday.com/cardiology/atherosclerosis/77716