Principal components of fitness: relationship to physical activity and lifestyle

Interrelationships between metabolic and cardiorespiratory health were examined in 350 healthy adults. Four principal components accounted for 66.7% of the variance in 172 males (M) and for 62.4% in 178 females (F). Factor 1, "obesity," related to body mass index, abdominal circumference, total skinfold thickness, and (M only) abdominal/hip circumference ratio. Factor 2, "cardiovascular fitness," had loadings from resting heart rate and PWC150/kg. Factors 3 and 4 were related to total cholesterol and HDL-cholesterol, respectively (plus blood pressures, particularly in F). Factor 1 was linked to caffeine consumption and to exercise frequency (F) or perceived intensity (M). Factor 2 was linked to perceptions of activity relative to others (M and F) and to the intensity of activity (M only). Factors 3 and 4 were associated with perceived fitness and physical activity relative to others. Because perceptions of physical activity and fitness lack consistency, it is suggested that health be judged more directly from simple measures of health related fitness that require little subject cooperation.