Evaluation of the interchangeability of VO2MAX and oxygen uptake efficiency slope

A reliable submaximal test for assessing cardiorespiratory function would be of interest in clinical practice. Baba et al. (1996) proposed the oxygen uptake efficiency slope (OUES) derived from the relation between oxygen uptake (VO2 [ml x min (-1) x kg (-1)]) and minute ventilation (VE [L x min (-1)]) during incremental exercise. We evaluated the validity of OUES by comparing maximal oxygen uptake (VO2MAX) predicted from OUES to measured VO2MAX in 50 healthy males who performed a maximal treadmill test. They had widely differing physical fitness levels (VO2MAX range, 32.7 to 80.2 mlO2 x min(-1) x kg(-1). Predicted VO2MAX was not significantly different (p > 0.99) from measured VO2MAX (56.8 7.0 vs. 56.8 8.8 mlO2 x min 1 kg(-1). The limits of agreement (Bland Altman, 1986) were plus or minus 10.5 mlO2 x min(-1) x kg(-1). Although OUES and VO2MAX were significantly correlated (r = 0.79), the wide interindividual variations in the difference between these two parameters may limit the usefulness of OUES in clinical practice.