A high volume of physical activity (PA) is associated with a lower risk for all-cause mortality vs. low-volume PA but a similar risk for clinical coronary artery disease (CAD). However, coronary artery calcium (CAC) is associated with an increased risk for clinical CAD regardless of the volume of PA, according to findings from the Cooper Center Longitudinal Study (CCLS) published April 21 in Circulation.

Jarett D. Berry, MD, et al., connected data collected from 26,724 participants (54 years old, 28% women) in the CCLS between 1987 and 2018 with Medicare claims data to evaluate the association between PA volume, CAC and all-cause mortality and clinical CAD. Self-reported PA level was categorized into four groups based on metabolic equivalent of task (MET)-minutes per week (MET-min/wk): low (<500), intermediate (500 to 1,499), intermediate (1,500 to 2,999) and high (≥3,000). The mean PA volume was 1,130 MET-min/wk; 8% reported exercising ≥3000.

Results showed that after nearly 21 years of follow-up, there were 811 acute myocardial infarction (AMI) hospitalizations, 1,636 composite CAD events (AMI plus revascularization) and 2,857 non-CAD deaths.

The risk for AMI was lowest in the two intermediate volume groups compared with the low volume group (hazard ratio [HR], 0.77 and 0.78). In the high-volume group, no association was found with the risk of AMI (HR, 0.95) and this group had the lowest risk for death (HR, 0.71).

Notably, the presence of CAC increased the risk for the composite CAD outcome across all PA categories, with a 29% increase in the high-volume group (p for interaction=0.969).

The authors write that "elevated CAC in high-volume exercisers is clinically relevant and should be treated similarly to CAC identified in other contexts." They also note that "although there is no evidence of an increased risk for mortality, there appears to be a limit to the benefit of PA for the reduction of CAD risk" when exercising >3000 MET-min/wk.