The twenty-four-hour energy expenditure (24h-EE) of 41 adults (21 males and 20 females) in sedentary life with light exercises was measured using a whole-body indirect human calorimeter at the National Institute of Health and Nutrition. In a chamber, the subjects were asked not to perform strenuous exercise except for the following prescribed activities, four times of 15-min cycling, four times of 15-min standing, and 15min of stepping. Basal metabolic rate (BMR) was measured in the postabsorptive state. The means and SDs of the measured BMR and 24h-EE were 1, 376±297 kcal and 2, 064±373kcal, respectively. The physical activity level (PAL) calculated as 24h-EE divided by BMR was 1.51±0.12, and the estimated PAL without the prescribed exercises was 1.38±0.12. The mean sleeping metabolic rate (mean energy expenditure for an overnight period)/BMR ratio was 1.03±0.08. These results indicate that the PAL values are higher than those assumed previously.