Oxygen consumption following exercise of moderate intensity and duration

To study the effects of exercise intensity and duration on excess postexercise oxygen consumption (EPOC), 8 men [age= 27.6 (SD 3.8) years, VO_2max = 46.1 (SD 8.5) ml min^-1 kg^-1] performed four randomly assigned cycle-ergometer tests (20 min at 60% VO_2max, 40 min at 60% VO_2max, 20 min at 70% VO_2max, and 40 min at 70% VO_2max). O₂ uptake, heart rate and rectal temperature were measured before, during, and for 1 h following the exercise tests. Blood for plasma lactate measurements was obtained via cannulae before, and at selected times, during and following exercise. VO₂ rapidly declined to preexercise levels following each of the four testing sessions, and there were no differences in EPOC between the sessions. Blood lactate and rectal temperature increased (P<0.05) with exercise, but had returned to preexercise levels by 40 min of recovery. The results indicate that VO₂ returned to resting levels within 40 min after the end of exercise, regardless of the intensity (60% and 70% VO_2max or duration (20 min and 40 min) of the exercise, in men with a moderate aerobic fitness level.