Energy study of a group of high school girls

Includes bibliographical references (pages 44-49)There is no data available on the energy expenditures of girls in late adolescence as they go about their normal activities. Tables of energy costs of activities of children do not apply to this age group and neither do the tables of costs of activities of adults be cause although growth rate has slowed down, growth is not complete. The primary objective of this study was to determine the energy expenditures of high school girls during three segments of the school day using respirometry and heart rate telemetry techniques. Ten girls with a mean age of 16.8 years served as subjects for this study. Regression equations of heart rate versus caloric expenditure were established for each subject. These were used to calculate average energy expenditure for each subject during class, during physical education class and during after school hours based on mean heart rate. The mean value of energy expenditure for class activities was 0.88, sd ??0.42 kilocalories per minute. During physical education class energy expenditure for the group was 2.42, sd ??0.2 0 kilocalories per minute. After school the girls expended 1.95 sd ??0.40 kilocalories per minute. Mean energy expenditure for the entire day was 2.09, sd ??0.35 kilocalories per minute. Energy expenditures were also calculated for the reclining,sitting and standing positions. These values were 0.88, sd ??0.19; 1.22, sd ??0.20; and 0.54, sd ??0.60 kilocalories per minute respectively. In addition three- day caloric intake and three-day activity diaries were obtained for each subject. The girls as a group are considered very sedentary. They spend 97.7 percent of their time in sleep, very light and light activities. Only 1.8 per cent of their time is spent in moderate activity and 0.04 per cent of their time is spent in strenuous activity. From the data collected it was calculated that the average daily total energy expenditure for this group of girls is 2412, sd ??281 kilocalories per day