An evidence-based multi-factorial model to predict the oxygen cost of ventilation during ramp-incremental cycle ergometry exercise

Introduction During maximal ramp-incremental exercise (RIE), the oxygen uptake–power output relationship ( V ˙ O 2 gain) may deviate from linearity near exhaustion. An increased oxygen cost of ventilation ( V ˙ O 2VENT ) is a plausible but under-quantified contributor. This study tested a non-linear multi-factorial model using measured V ˙ O 2VENT and six predictors: resting expired ventilation ( V ˙ E ), weight, height, age, V ˙ O 2 peak, and maximal heart rate (HRMax) to 1) estimate V ˙ O 2VENT and its contribution to maximal oxygen uptake ( V ˙ O 2 max) in an independent dataset and 2) determine whether correcting V ˙ O 2 by V ˙ O 2VENT ( V ˙ O 2VCORR ) alters V ˙ O 2 max and V ˙ O 2 gain estimates. Methods Published data from 42 participants (11 women, 31 men; 29 ± 6.5 years; V ˙ O 2 max = 4.02 ± 1.06 L min −1 ) were used to derive the model. Leave-one-out cross-validation (LOOCV) was used to assess validity, with predictive accuracy and coefficient stability evaluated via bootstrap resampling. The model was applied to an independent RIE dataset to generate V ˙ O 2VCORR , which was compared with uncorrected <mml:mi mathvariant="normal