The relationships among physical activity, physical fitness, stress, and coronary artery disease (CAD) risk factors

Physical inactivity and psychosocial stress have both been identified as risk factors for CAD. Regular physical activity (resulting in a state of physical fitness) positively impacts several CAD risk factors and also may decrease stress. It is unknown, however, if regular physical activity can reduce the deleterious effects of stress on CAD risk factors. This investigation examined physical activity, physical fitness, stress, and CAD risk factors in a population with a stressful work environment. The variables were assessed on 412 male and 47 female police officers from the City of Austin. Systolic and diastolic blood pressure, total cholesterol, and HDL cholesterol were collected through screenings. Smoking habits, physical activity level, type A behavior score, perceived general stress, perceived job stress, and job strain (e.g., decision latitude and psychological demands) were assessed from self-report. Percent body fat and maximal time on the treadmill (physical fitness measure) were collected from existing data. Physical fitness level was negatively related to percent fat, number of cigarettes smoked/day, and diastolic blood pressure. Higher physical fitness levels were associated with higher HDL cholesterol and type A score. No significant relationship was found regarding physical activity for CAD risk factors. Type A score was higher with higher general stress and job stress levels. General stress was also positively related to number of cigarettes smoked/day and diastolic blood pressure. Decision latitude and psychological demands were not related to any CAD risk factors. Stress scores were not different across physical activity or physical fitness levels. There were interactions noted between the independent variables job stress, composite stress, physical activity, physical fitness, and some risk factors. HDL cholesterol remained enhanced in the high active and fit levels at high stress. Smoking habits were lower with higher stress in the high active and fit, but higher at lower activity and fitness levels with higher stress levels. These findings suggest that physical fitness, general stress, and job stress are associated with several CAD risk factors. Physical activity/physical fitness may mediate the deleterious effects of stress for some risk factors.