The importance of physical fitness versus physical activity for coronary artery disease risk factors: a cross-sectional analysis.

Numerous epidemiological investigations have shown that low physical fitness and low physical activity are related to the incidence of coronary artery disease (CAD). Most studies, however, have not examined both variables concurrently to determine which has the strongest association with CAD risk. The purpose of this investigation was to cross-sectionally examine the relationships among physical fitness, physical activity, and risk factors for CAD. Male law enforcement officers (N = 412) from the City of Austin, Texas, were subjects for this study. Physical fitness, physical activity, and risk factors for CAD were assessed through health screenings and from data collected as part of an annual physical fitness assessment. Multivariate analysis of covariance revealed that physical fitness, but not physical activity, was related to several single CAD risk factors. Percent body fat, smoking habits, and Type A behavior score were negatively related to physical fitness level, and high density lipoprotein (HDL) cholesterol was positively related to physical fitness level. Univariate analysis of variance found both physical fitness and physical activity to be significantly related to a composite CAD risk score. Low physical fitness and low physical activity were associated with a high CAD risk score. These data suggest that physical activity must be sufficient to influence physical fitness before statistically significant risk-reducing benefits on single CAD risk factors are obtained, although minimal engagement in weekly vigorous activity provides a significant benefit for the composite CAD risk score. It is plausible, however, that physical fitness is a stronger measure than physical activity and optimally characterizes the relationship among physical activity and CAD risk factors.