Characterizing The Volume Of Physical Activity Related To Risk For Coronary Heart Disease Events: Findings From The Cooper Center Longitudinal Study

PURPOSE: While low levels of physical activity (PA) are associated with an increased risk for coronary artery disease (CAD) events, recent evidence suggests that individuals who participate in high volume aerobic exercise have a higher prevalence of coronary atherosclerosis. However, the association between high volume PA and CAD remain incompletely understood. Therefore, we sought to characterize the relationship between PA dose and acute myocardial infarction (AMI) events. METHODS: Individual participant data from the Cooper Center Longitudinal Study were linked to Medicare claims files. Leisure time PA volume (MET-min/week) was determined by self-report. All other risk factors were measured in the standard fashion. AMI events were determined from Medicare claims files using established algorithms. A multivariable-adjusted proportional hazards illness-death model with random shared frailty was used to estimate hazard ratios for incident AMI. RESULTS: We included 26,724 participants (age 54; 28% women) with baseline PA and later life Medicare claims. Mean PA volume was 1,130 MET-min/week, with 1,997 (7.5%) of participants reporting ≥3,000 MET-min/week. After a mean 20.5 years of follow-up (including 8.0 years surveillance within Medicare), we observed 811 AMI events. The lowest adjusted risk [HR (95% CI)] for AMI occurred in intermediate to high PA volumes (500 to 1,499 MET-min/week) [ 0.77 (0.65-0.91)] and (1,500 to 2,499 MET-min/week [0.78 (0.63-0.95)] vs. < 500 MET-min/week. Additionally, there was no significant difference in risk between very high volume PA (≥ 3,000 MET-min/wk) and any of the lower PA groups. CONCLUSION: Those reporting 500-2,499 MET-min/week of PA had the lowest adjusted risk of AMI.