A longitudinal study of energy expenditure in males during steady-state exercise

Our purpose was to investigate longitudinal changes in gross energy expenditure (GEE) of 20 middle-aged and older men during submaximal exercise in 1969 and in 1985. GEE (kcal/min) was estimated using the caloric equivalent for each liter of oxygen consumed at the measured respiratory exchange ratio during submaximal exercise. The men performed a 10-min submaximal cycle ergometer exercise test at a power output (PO) of 100 W. Pedalling frequency was 50 rpm. Results showed a significant 5.9% decrease in GEE (p less than .01) from 8.5 +/- 0.8 (M +/- SD) kcal/min in 1969 to 8.0 +/- 0.4 (M +/- SD) Kcal/min in 1985. In addition, the effects of chronological age and leisure time physical activity on GEE were assessed and found to be nonsignificant, although a significant decrease in GEE over time (p less than .02) was observed in both groups. The present results support a decrease in GEE in middle-aged and older men over the 16-year time period. Furthermore, this decrease in GEE persisted regardless of chronological age or leisure time physical activity status.