Abstract
BACKGROUND: Exercise confers numerous health benefits, including a reduction in all-cause and cardiovascular (CV) mortality. However, conflicting evidence suggests that high-volume endurance exercise may increase coronary artery calcification, a robust predictor of CV events. This systematic review investigated the relationship between exercise volume and coronary artery calcium (CAC) scores. METHODS: A systematic search of Medline, Embase, PubMed, and the Cochrane Library (1990 to November 26, 2025) was conducted. Studies reporting exercise volume and CAC scores were included. The methodological index for nonrandomized studies (MINORS) scale was implemented to test study quality. Exercise volume (minutes per week) was stratified into 4 categories: low; moderate; moderate-high; and high. RESULTS: A total of 33 studies met the inclusion criteria: 15 reported higher CAC scores in their highest-volume groups; 8 showed no association or inverse associations; and 10 included single-cohort data. Nine of 12 comparative studies with participants exercising > 450 min/wk showed higher CAC scores in high-volume exercisers. The majority of the 9 studies reporting clinical outcomes showed no relationship or an inverse association between exercise volume and mortality or CV events. Among 5 studies assessing plaque composition, 4 reported a more benign, calcified plaque composition among their high-volume exercisers, representing a potential mechanism for the lower risk of CV events and mortality reported in this population, compared to that of less-active individuals with similar CAC scores. CONCLUSIONS: High-volume exercisers may have higher CAC scores compared to less-active cohorts. Despite elevated CAC scores, lower mortality and CV event rates observed in these groups challenge the clinical significance of this observation. REGISTRATION: PROSPERO CRD42024607693.