Minute-by-Minute Oxygen Requirement and Work Efficiency for Constant- Load Exercise of Increasing Duration

Abstract

To study the effects of duration of constant-load exercise on work efficiency (O₂ equivalent of exercise/total O₂ requirement of performing the exercise) 70 separate experiments on 14 subjects were performed (3 tests of 1,2, 3, 4, and 7-min duration each). Statistical analysis of oxygen requirements and work efficiency for each test duration showed that non steady-state work of short duration was significantly lower (p < 0.01) compared to work performed for longer durations, i.e., steady-state work. For all exercise tests net 15-min postexercise O₂ uptake exceeded the oxygen uptake lag (deficit) almost twofold.