Effects of moderate-intensity exercise on diet-induced increase in resting oxygen uptake

We measured and compared the diet-induced increase in resting oxygen uptake (DIIROU) after moderate-intensity exercise (MIE) with the DIIROU after high-intensity intermittent exercise (HIIE). Eight healthy adult males participated in six testing sessions, including the measurement of resting oxygen uptake with and without lunch after MIE, HIIE, and as a non-exercise control. The MIE was 30 min of exercise at an intensity of 70% VO2max, and the HIIE consisted of seven to eight 20 second bouts of exhaustive exercise at 170% VO2max with 10-sec rests between the bouts. The exercise time of the HIIE for the no-lunch (fasting) experiment (144.1 ± 10.0 sec) was not significantly different from that for the lunch experiment (142.8 ± 10.3 sec). Lunch (713 kcal) was served for the lunch experiment at 12:00, which corresponds to ~1.5 hr after each exercise. Compared to the non-exercise control results, the accumulated oxygen uptake (AOU) of the MIE and HIIE were significantly higher from the end of the exercise until 11:30 (p < 0.001). However, no difference in AOU was noted from 11:30 to 12:00 between the control and MIE or HIIE results, suggesting that excess post-exercise oxygen consumption wore off before 12:00. The values of DIIROU (quantified as the difference in AOU between the lunch and fasting experiment from 12:00 to 16:00) after HIIE, MIE, and the non-exercise control were 132.7 ± 37.2, 102.8 ± 48.0, and 77.8 ± 40.7 ml/kg, respectively. The ΔDIIROU for the MIE (25.0 ± 17.8 ml/kg) calculated as the difference in DIIROU from the non-exercise control was significantly less than that of the HIIE (55.0 ± 25.4 ml/kg) (p < 0.01). These results may indicate that MIE potentiates a diet-induced increase in resting oxygen uptake, even though this effect was less than that of HIIE and was quantitatively small.