Lifelong Endurance Exercise and Its Relation With Coronary Atherosclerosis

The fittest live the longest and often do so with the highest quality of life. The story is so compelling that it was once proposed that running marathons conferred complete immunity to coronary atherosclerosis.¹ Today however, we know that is far from the truth. Obstructive coronary artery disease is the most common cause of exercise-related sudden death among aging athletes,² a group that typically harbors multiple traditional risk factors.³ In addition, several prior studies have documented asymptomatic coronary artery calcification in this population.^4,5 To date, available data suggest that master athletes may develop coronary calcification but are unlikely to harbor the lipid-rich atherosclerotic plaques that underlie acute coronary syndromes. It has thus been proposed that most coronary calcification among asymptomatic athletes are a relatively benign phenotype caused by the mechanical wear and tear of high-volume coronary blood flow.⁶ Much like the hardened fibrous soles on a runner’s foot, perhaps coronary calcium is really simply coronary “callusification.”

Relevant data from the Master@Heart study were recently presented at the 2023 ACC Scientific Sessions and simultaneously published in the European Heart Journal.⁷ This study utilized CT coronary angiography to compare coronary artery morphology between lifelong endurance athletes and normally active healthy controls. Importantly, both athletes and control participants were free of traditional atherosclerotic risk factors at the time of enrollment. Lifelong endurance athletes were more likely than controls to have one or more coronary plaque and one or more plaque in a proximal coronary artery segment. Surprisingly and in contrast to prior data, lifelong athletes were found to have a higher burden of both calcific and noncalcific plaques. The authors conclude that “lifelong endurance sport participation is not associated with a more favorable coronary plaque composition compared to a healthy lifestyle.”

The field of sports cardiology remains plagued by the absence of longitudinal prospective studies that report both phenotypic profiles and corollary outcomes. The Master@Heart study thus represents a big step forward and immediately reinforces a fundamental tenant of sports cardiology. Put simply, no amount of exercise confers definitive protection from atherosclerotic coronary disease. There is simply no such thing as an athlete who does enough exercise, or looks healthy enough walking into the clinic, to obviate the need for comprehensive risk factor profiling and aggressive preventive intervention. I have already begun to integrate the valuable Master@Heart data into patient education and counseling on this topic.

Despite this progress, critical questions remain unanswered. Why do lifelong endurance athletes without the typical causal mediators of atherosclerosis still get coronary disease? It is possible, if not probable, that we still incompletely understand and thus fail to address the complete equation-defining risk. Rather than simply “too much exercise,” unmeasured confounders common among aging athletes including genetic predisposition, chronic psychosocial stress, suboptimal dietary choices, and unhealthy early life habits — factors I refer to as the “carefree 20s and 30s” — deserve more attention both in clinic and in research. Perhaps more importantly, what are the clinical implications of abnormal coronary morphology among aging athletes? At present, we have no data to suggest that high amounts of exercise increase adverse atherosclerotic disease outcomes. While we await answers to these important issues, I personally think it is premature to leverage the Master@Heart data to discourage patients from high-level endurance exercise. Endurance athletes live long and live well largely due to their exercise-centric lifestyle. While it may be tempting to advise less exercise, this data-free recommendation will almost certainly do more harm than good.

References

1. Bassler TJ. Marathon Running and Immunity to Atherosclerosis. Ann N Y Acad Sci. 1977;301(1):579-592. https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/j.1749-6632.1977.tb38231.x
2. Kim JH, Malhotra R, Chiampas G, et al. Cardiac Arrest During Long-Distance Running Races. N Engl J Med. 2012;366(2):130-140. https://www.nejm.org/doi/full/10.1056/NEJMoa1106468
3. Shapero K, Deluca J, Contursi M, et al. Cardiovascular Risk and Disease Among Masters Endurance Athletes: Insights From the Boston MASTER (Masters Athletes Survey To Evaluate Risk) Initiative. Sports Med Open. 2016;2:29. https://sportsmedicine-open.springeropen.com/articles/10.1186/s40798-016-0053-0
4. Merghani A, Maestrini V, Rosmini S, et al. Prevalence of Subclinical Coronary Artery Disease in Masters Endurance Athletes With a Low Atherosclerotic Risk Profile. Circulation. 2017;136(2):126-137. https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.116.026964
5. Aengevaeren VL, Mosterd A, Braber TL, et al. Relationship Between Lifelong Exercise Volume and Coronary Atherosclerosis in Athletes. Circulation. 2017;136(2):138-148. https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.117.027834
6. Baggish AL, Levine BD. Coronary Artery Calcification Among Endurance Athletes: "Hearts of Stone". Circulation. 2017;136(2):149-151. https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.117.028750
7. De Bosscher R, Dausin C, Claus P, et al. Lifelong Endurance Exercise and Its Relation With Coronary Atherosclerosis. Eur Heart J. 2023 Mar 6. doi: 10.1093/eurheartj/ehad152. Online ahead of print. https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehad152/7069916