Abstract

Physical exercise is prescribed to older individuals to increase cardiovascular fitness and improve body composition. However, there is limited information on the effect of exercise on total energy expenditure (TEE) and its components. We therefore determined the effects of short-term endurance training in 11 elderly volunteers (56-78 years) on changes in 1) TEE, from doubly labeled water; 2) resting metabolic rate (RMR), from respiratory gas analysis, 3) the energy expenditure of physical activity (EEPA), aside from that associated with the training program, and 4) body composition from a combination of body density with total body water. Endurance training increased maximum oxygen consumption (VO2max) by 9% (2.00 +/- 0.67 to 2.17 +/- 0.64 l/min; P < 0.05) and RMR by 11% (1,596 +/- 214 to 1,763 +/- 170 kcal/day; P < 0.01). There was no significant change in TEE (2,408 +/- 478 to 2,479 +/- 497 kcal/day) before and during the last 10 days of endurance training because of a 62% reduction in EEPA (571 +/- 386 to 340 +/- 452 kcal/day; P < 0.01). There was no change in body mass, but fat mass decreased (21.6 +/- 6.6 to 20.7 +/- 6.6 kg; P < 0.05). The increase in fat-free mass (49.5 +/- 9.0 to 50.4 +/- 9.1 kg; P < 0.05) was explained by an increase in body water (35.9 +/- 6.5 to 36.8 +/- 6.3 kg; P < 0.05). We conclude that in healthy elderly persons, endurance training enhances cardiovascular fitness, but does not increase TEE because of a compensatory decline in physical activity during the remainder of the day.