Coronary artery calcification and high-volume physical activity: role of lower intensity vs. longer duration of exercise.

Aims: While high-volume physical activity (PA) has been linked to elevated coronary artery calcification (CAC), the role of intensity vs. duration of PA has not been investigated. The purpose of the study was to examine the role of intensity vs. duration of PA in relation to CAC.

Methods And Results: Data are from 23 383 apparently healthy men who completed a PA questionnaire and underwent CAC scanning as part of a preventive examination. Self-reported PA was categorized into four groups of average intensity and weekly duration of PA [average intensity: 1, 3-5.9, 6-8.9, and 9-12 metabolic equivalents of task (METs); weekly duration: 0, > 0-<2, 2-<5, and ≥5 h/week]. Mean CAC and CAC ≥ 100 Agatston units (AU) were regressed separately on continuous or categorical average intensity and weekly duration of PA. The mean (standard deviation) age was 51.7 (8.3) years, and mean CAC was 174.8 (543.6) AU with 23.5% of men presenting with CAC ≥ 100 AU. Higher average intensity of PA was related to lower mean CAC [-3.1%/MET, 95% confidence interval (CI): -4.6, -1.6%/MET] and lower relative risk (RR) of CAC ≥ 100 AU (RR: 0.99, 95% CI: 0.98, 1.00/MET). Opposite trend was observed for the duration component wherein higher weekly duration of PA was significantly associated with greater mean CAC and RR of CAC ≥ 100 AU.

Conclusion: Elevated CAC was associated with lower average intensity and longer duration of PA in men, providing new insight into the complex relationship between leisure-time PA behaviours and risk of CAC.