Physical activity during leisure time and on the job have been measured with standardized interview techniques in 1,513 normal men, aged 40-55 years, who were regularly employed in different industries. Physical fitness was simultaneously estimated by measuring the work load at which a heart rate of 150 bpm was reached on a standardized exercise test. The median energy expenditure from leisure time activities above the basal metabolic rate was 195 kcal/day; 19% of these activities were classified as heavy, 37% as moderate and 43% as light intensity. The median energy expenditure from job physical activity was 1,676 kcal/day including basal metabolic rate. The median physical fitness level was 125 W. The leisure time activity score was significantly related to physical fitness through the light and the heavy intensity subscores. Independently, job physical activity was also significantly related to physical fitness. However, both activity scores accounted for only 2% of the variance in physical fitness. The data illustrate an overall low energy expenditure profile of middle-aged normal men and a low order relationship between physical activity pattern and physical fitness.