Studies on physical activity, physical fitness, and health have been hampered because of invalid, unreliable, or impractical measures of physical activity. This report examines the validity of sedentary traits (resting tachycardia, obesity, and low vital capacity) as predictors of physical fitness as assessed by a maximal treadmill exercise test. Study participants were women (n = 3,943) and men (n = 15,627) with at least one visit to the Cooper Clinic in Dallas, Texas. Association of the sedentary traits with physical fitness was examined by multiple regression analyses. Sedentary traits were associated with physical fitness in all age and sex groups, accounting for 12-40% of the variance in treadmill time. When smoking, a simple physical activity index, and sedentary traits were included in a model to predict physical fitness, R2 values ranged from 0.20 to 0.53 in women and 0.45 to 0.61 in men and were significant at p less than 0.0001. These models account for approximately twice as much variance in physical fitness as has been reported previously. The addition of sedentary traits measurements to a simple physical activity index provides a valid estimate of physical fitness in epidemiologic studies.

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Associations between changes in treadmill time and changes in coronary heart disease risk factors were studied in 753 middle-aged men seen between 1978-1981 at the Cooper Clinic in Dallas, Texas. Men were free of known disease at baseline. Significant increases (p less than 0.01) in exercise habits and treadmill time were seen over the course of the study; average follow-up was 1.6 years. In bivariate analyses, increases in treadmill time and weight loss were associated with improvements (p less than 0.01) in risk factors. Multiple regression models were calculated for several risk factors with age, length of follow-up, change in weight, and change in treadmill time as independent variables. After controlling for confounding, increase in treadmill time was independently associated with decreases in the total cholesterol/high density lipoprotein-cholesterol ratio (p less than 0.01) and serum uric acid (p less than 0.05). High density lipoprotein-cholesterol rose with increase in treadmill time (p less than 0.05).

A longitudinal study was performed to determine differences in physiologic variables, health behaviors, risk factors, or clinical status between former athletes (FA) (N = 345) and nonathletes (NA) (N = 75). The subjects, 420 self-referred white males aged 25-60 years old, were examined for prior athleticism and health. Athleticism was determined through self-reported high school or college athletic history. Baseline physiologic and health behavior characteristics were not different between the two groups. Of those study participants (N = 203 FA, 48 NA) who were sedentary at baseline, 208 (N = 167 FA, 41 NA) voluntarily began an exercise program during the followup period (average followup = 56 months). These numbers correspond to exercise adoption rates of 82 and 85% for FA and NA respectively, and were not statistically different (95% CI FA = 0.76, 0.88, NA = 0.73, 0.97). Repeated measures analysis of covariance was performed to determine if physiologic responses to adoption were different between FA and NA. No statistically significant difference was found between the two groups, time effects were similar in the two, and no significant interaction of time by group was observed. We conclude that prior athleticism has little apparent impact on health and health behaviors, thus suggesting that contemporaneous exercise has more impact on clinical variables.

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