Objective: To investigate alterations in whole body fat oxidation after 7 and 14 weeks of progressive endurance training in sedentary elderly subjects.
Design: Longitudinal, 14 weeks of progressive endurance training on a cycle ergometer (3 training sessions per week). Full sets of measurements were performed before, and after 7 and 14 weeks of training.
Subjects: 13 healthy sedentary subjects (5 men, 8 women) (age 62.8 +/- 2.3 y).
Measurements: 24 h indirect calorimetric measurements under standardised conditions: light-activity programme, fixed food composition, neutral daily energy balance. Body composition (by isotope dilution and skinfold thicknesses). Maximal oxygen consumption.
Results: Loss of 0.7 kg fat mass in the first 7 weeks of training and a further 2.4 kg of fat in the second 7 weeks. There was a transient increase in sleeping fat oxidation after 7 weeks of training (+26.1%), associated with transient increase in daily fat oxidation (+/- 11.9%), but fat oxidation then returned to baseline values in the second 7 weeks. There was a correlation between within-subject changes in sleeping fat oxidation after 7 weeks of training and variations in FFM (r = 0.62, P = 0.02) and maximal oxygen consumption (r = -0.56, P < 0.05).
Conclusion: In sedentary elderly subjects, progressive endurance training was associated with a transient increase in sleeping fat oxidation and daily fat oxidation. In free-living conditions, possible changes in daily fat oxidation may have induced a negative fat balance, as judged by fat mass loss.