Aim: We examined the effects aerobic and anaerobic metabolisms on O₂ uptake (VO₂) and work rate (WR) relationships during an incremental ramp exercise test.

Material and Methods: Eighteen healthy untrained male subjects performed an incremental ramp exercise test (15 W/min) to the limit of tolerance using an elctromagnetically-braked cycle ergometer. Ventilatory and pulmonary gas exchange were measured by a turbine volume transducer and a mass spectrometry and estimated breath-by-breath. Aerobic to anaerobic metabolic transition (anaerobic threshold) was estimated non-invasively using ventilatory and pulmonary gas exchange indices.

Results: The maximal VO₂ and WR were 3.108�0.542 l/min and 246 � 39 W, respectively. VO₂ at the anaerobic threshold was 1.760�0.31 l/min (56% of maximal VO₂). During exercise, VO₂ increased linearly with WR throughout ramp phase (0,9899�0.006) and also aerobic (0,9689�0.02) and anaerobic (0,9787�0.01) regions of the test. Furthermore, the ratio of DVO₂ /DWR was 10.3 � 1.2 ml/min/W.

Conclusion: Consequently, these results may suggest that VO2 is more related to the mitochondrial respiration rather than O₂ supply to exercising muscles.