A study on the daily physical activity of junior high school students in Japan.

The purpose of this study was to estimate daily energy expenditure (EE) and daily activity factor (DAF: EE/basal metabolism - 1) of junior high school students in Japan using heart rate (HR) monitoring method. Daily activity recording and 24 hour HR monitoring were measured in all the subjects. The relational formulas between HR and oxygen consumption were obtained from bicycle ergometer test. Subjects were 112 junior high school students (68 male and 44 female) from the 1st to the 3rd year. The averages of EE (kcal/kg) of the 1st, 2nd, and 3rd year students were 54.3, 46.7, and 44.5 (kcal/kg) for males and 50.1, 44.4, and 40.5 (kcal/kg) for females respectively. In the same way DAF were 0.80, 0.61, and 0.59 for males and 0.77, 0.65, and 0.51 for females. It was shown that EE (kcal/kg) and DAF have a tendency to decrease as school year increases in both male and female students.