THE INFLUENCE OF EXERCISE ON THE ENERGY-REQUIREMENTS OF ADULT MALES IN THE UK

Energy expenditure was measured over 10 d using the doubly-labelled wa ter (DLW) and activity diary methods in summer and winter in subjects with 'light' occupations bat leisure activities which ranged from 'non -active' to 'very active', The basal metabolic rate (BMR) and the ener gy cost of activities were determined by indirect calorimetry. The Dep artment of Health (1991) predicted BMR for the group (6.89 (SD 0.30) M J/d; n 18) was not significantly different from the measured value (7. 17 (SD 0.70) MJ/d; n 18). The range of DLW-derived expenditure values within the group was BMR x 1.41 to 2.41. The largest seasonal change w ithin individuals was BMR x 0.5. The energy expenditure of the group a s a whole was lower in winter (BMR x 1.88; so 0.33; n 9) than summer ( BMR x 2.01; SD 0.30; n 9) though the difference was not statistically significant, The average summer and winter DLW-derived expenditure was BMR x 1.96 (SD 0.31; n 17), The activity diary estimate of expenditur e was BMR x 1.79 (so 0.32; n 17), In a subset of the group who were re presentative of the most active 26% of all adult males in the UK, the DLW-derived expenditure was BMR x 2.08(so 0.24; n 11), This is higher than the highest Department of Health (1991) estimate of BMR x 1.6 for individuals in light occupations. The measured energy costs of low-in tensity activities were similar to those presented in the Department o f Health (1991) report but the value determined for running (BMR x 13. 08; so 2.4; n 6) was higher than the highest value in the report (BMR x 6 to 8), The results indicate that the recent Department of Health ( 1991) reference values for energy may underestimate the expenditure of a significant proportion of the UK population largely because the ene rgy costs of activity used in the report to calculate expenditure do n ot accurately reflect those achieved during active leisure in individu als who take regular exercise.