Written by Joyce Smith, BS. This study validated that high coronary arterial calcification (CAC) is associated with higher levels of physical exercise but not with increased mortality.
For a number of years research has queried the potential adverse effects of long-distance endurance exercise, particularly with respect to the development of coronary artery calcification (CAC) 1. Whether coronary plaques are more abundant in athletes remains controversial 2. Concerns about the risks of high-intensity physical activity, such as long-distance running, cycling, triathlons and other sports, emerged in Germany in 2008 when researchers studied 108 healthy male marathon runners in the Heinz Nixdorf Recall study. Initial analysis revealed that the amount of CAC found among
3+6athletes and their age-matched controls was very similar; yet, when matched with healthy controls with the same CVD risk factors, the marathon runners had a higher degree of calcification 3. In the Copenhagen City Heart Study, individuals who jogged 1.0 to 2.4 hours/week had a 71% reduced mortality compared to nonjoggers; however, strenuous joggers appeared to have higher mortality 4. Other studies have shown that those with the highest levels of physical activity had calcified coronary plaques that were thought to be more stable and were less susceptible to rupture 5. One such study found that 72.7% of lifelong endurance athletes had more CAC that was hardened and more stable with less chance of rupture and myocardial infarct (MI) compared to 61.5% of their sedentary controls with plaques of predominantly mixed morphology that were more susceptible to rupture 5. These inconsistencies in study findings and the absence of clinical recommendations to guide physically active people with CAC, led to the following study which assessed whether high levels of CAC were associated with increased mortality in very physically active men.
The Cooper Center Longitudinal Study 6 is an observational study of 21,758 participants from the Cooper Clinic, a preventive medicine facility, who met the exclusion criteria and were evaluated based on a history of physical activity and CAC scanning from January 13, 1998, through December 30, 2013, with a follow-up completed on December 31, 2014. Baseline mean age was 51.7 ± 8.4 years. Self-reported physical activity was categorized into at least 3000 (n = 1561), 1500 to 2999 (n = 3750), and less than 1500 (n = 16 447) metabolic equivalents of task (MET)–minutes/week (min/wk.). The CAC scores were categorized into at least 100 (n = 5314) and less than 100 (n = 16 444) Agatston units (AU).
Analyzed data to determine whether CAC in athletes was associated with an increased risk of mortality revealed that participants who engaged in the high level of exercise (at least 3,000 MET-min/wk) were more likely to have CAC; however, nearly 75% of study participants had low levels of CAC (less than 100 AU) regardless of their physical activity level. Those with a CAC score of less than 100 AU and who participated in high-volume physical activity (at least 3000 MET-min/wk), had a 48% lower risk of all-cause mortality compared with those who exercised less than 1,500 MET-min/wk. Those with the highest levels of physical activity also had lower mortality than those with the lowest levels. The authors suggest that the high-volume exercisers ( > than 3,000 MET- min/wk) who exercised for about 8 hours per week, a volume that is greater than the daily recommended physical activity guidelines for health, may be exercising because they enjoy the sport rather than exercising for health reasons. Even after a 10- year follow-up, researchers found that higher levels of CAD, while associated with higher levels of physical activity, were not associated with increased cardiovascular mortality.
A predominantly white, well-educated population and access to good health care that prevented generalizability to other populations, limited statistical power and the elimination of potential confounders were all cited as study limitations.
Source: 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. 2019; Epub ahead of print.
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Posted December 21, 2020.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
References:
- 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.
- Baggish AL, Levine BD. Coronary Artery Calcification Among Endurance Athletes: “Hearts of Stone”. Circulation. 2017;136(2):149-151.
- Möhlenkamp S, Lehmann N, Breuckmann F, et al. Running: the risk of coronary events : Prevalence and prognostic relevance of coronary atherosclerosis in marathon runners. Eur Heart J. 2008;29(15):1903-1910.
- Schnohr P, O’Keefe JH, Marott JL, Lange P, Jensen GB. Dose of jogging and long-term mortality: the Copenhagen City Heart Study. J Am Coll Cardiol. 2015;65(5):411-419.
- Aengevaeren VL, Mosterd A, Braber TL, et al. Relationship Between Lifelong Exercise Volume and Coronary Atherosclerosis in Athletes. Circulation. 2017;136(2):138-148.
- 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 cardiology. 2019;4(2):174-181.
