Effects of 14 weeks of progressive endurance training on energy expenditure in elderly people

Effects of progressive endurance training on energy expenditure (EE) were studied in thirteen elderly sedentary subjects (62.8 (SD 2.3) years) after 7 and 14 weeks of training. Daily EE (DEE) and energy cost of the various usual activities were measured over 48 h by whole-body indirect calorimetry. Free-living DEE (DEEFLC) was calculated from 7 d activity recordings and the energy costs of activities were measured in the calorimeters using the factorial method. DEEFLC did not vary significantly throughout the training period despite the additional energy cost of training sessions (0.60 (SD 0.15) MJ/d), because energy expended during free-living activities (EEACT) decreased by 4.8 (SD 7.1) % (P < 0.05) and 7.7 (SD 8.6) % (P < 0.01) after 7 and 14 weeks of training respectively. Measurements in the calorimeters showed that sleeping metabolic rate transiently increased by 4.6 (SD 3.2) % after 7 weeks of training (P < 0.001) and returned to its initial level after 14 weeks of training. BMR was 7.6 (SD 7.0) % (P < 0.01) and 4.1 (SD 6.1) % (P = NS) higher after 7 and 14 weeks of training respectively, than before training. Likewise, diet-induced thermogenesis increased from 3.7 (SD 2.5) to 7.2 (SD 2.8) % energy intake after 7 weeks of training (P < 0.05), and returned to its initial level after 14 weeks of training (4.2 (SD 2.6) % energy intake). Despite these changes, energy expended during activities and the corresponding DEE did not vary throughout the training period. It was concluded that: (1) DEEFLC remained constant throughout the training period due to a compensatory decrease in free-living EEACT; (2) progressive endurance training induced a transient increase in sleeping metabolic rate, BMR and diet-induced thermogenesis after 7 weeks which was not reflected in the energy expended during activities and DEE.