Thermogenic response to a meal and exercise in aerobically-trained, resistive-trained and non-trained subjects

The purpose of this study was to examine the metabolic response to a 763 KCAL mixed meal at rest, during exercise at 50% VO$\sb2$ max and 3 hours post-exercise in aerobically-trained (AT, n = 8) resistive-trained (RT, n = 8) and non-trained (NT, n = 8) subjects. Average VO$\sb2$ max was 60.7 $\pm$ 2.3 ml/kg. min, 52.9 $\pm$ 2.2 ml/kg. min and 51.1 $\pm$ 2.2 ml/kg. min for the AT, RT and NT groups respectively. Average percent fat was 13.7 $\pm$ 1.2, 12.7 $\pm$ 1.9 and 16.9 $\pm$ 1.4 for the AT, RT and NT groups. Oxygen uptake was measured by indirect calorimetry every half hour, on four nonconsecutive days (postabsorptive, PA; postabsorptive with exercise, PAX; postprandial, PP; and postprandial with exercise, PPX) for four hours. The thermic effect of food (TEF) without exercise (PP minus PA) and the TEF during exercise (PPX minus PAX) was not significantly different among groups. Additionally, the meal failed to increase oxygen uptake during exercise compared to oxygen uptake without a meal. The TEF post-exercise was significantly lower for the AT and RT groups. The total TEF over four hours was equivalent to 4.86 $\pm$ 1.62, 5.22 $\pm$ 1.80 and 9.36 $\pm$ 5.04 liters of oxygen for the AT, RT and NT groups respectively. Respiratory exchange ratios (R) during the PA and PAX conditions were significantly lower for the AT group compared to the RT and NT groups; while the AT group was only significantly lower than the RT group post-exercise. During the PP condition, R was significantly lower for the both the AT and RT groups during rest and post-exercise, but no significant differences among groups was observed during exercise. The combination of a meal plus exercise failed to potentiate the TEF during exercise. The results of this study fail to demonstrate a lower TEF during non-exercise and exercise conditions in aerobically-trained and resistive-trained subjects compared to non-trained subjects; however, a decreased TEF was observed in both the AT and RT groups post-exercise.U of I OnlyETDs are only available to UIUC Users without author permissio