Purpose: The primary objectives were to 1) examine the dose-response relationship between physical activity and mortality in individuals with CAD, and 2) determine whether the aforementioned relationship is consistent within strata of other personal characteristics.
Methods: Subjects included 1045 elderly men and women with CAD from the Cardiovascular Health Study. In the first set of analyses, the dose-response relationship between baseline leisure-time physical activity level and all-cause mortality risk over 9 yr was determined using Cox proportional hazards regression models. Next, the subjects were stratified based on several different characteristics, and the consistency of the relationship between baseline leisure-time physical activity and mortality risk within the various strata was determined.
Results: Baseline leisure-time physical activity was related to all-cause mortality risk in a curvilinear dose-response manner such that greater differences in mortality risk were seen at the lower end of the energy expenditure scale, with a plateau occurring at approximately 4000 kcal x wk(-1). Within various strata of sex, age, smoking, adiposity, self-perceived health status, number of comorbid conditions, and type of CAD; the relative risks of mortality were lower in active participants (>/=1500 kcal x wk(-1)) in comparison with inactive participants (<1500 kcal x wk(-1)).
Conclusion: This study highlights the inverse graded relationship between physical activity and all-cause mortality in men and women with CAD. Physical inactivity was a risk factor for mortality regardless of whether the subjects were men or women, old or very old, smokers or nonsmokers, lean or overweight, or otherwise healthy or unhealthy.