Prediction of peak oxygen uptake in men using pulmonary and hemodynamic variables during exercise.

Purpose: Many attempts have been made to predict peak VO 2 from data obtained at rest or submaximal exercise. Predictive submaximal tests using the heart rate (HR) response have limited accuracy. Some tests incorporate submaximal gas exchange data, but a predictive test without gas exchange measurements would be of benefit. Addition of stroke volume and pulmonary function (PF) measurements might increase the predictability of a submaximal exercise test. Methods: In this study, an incremental exercise test (10 W.min -1 ) was performed in 30 healthy men of various habitual activity levels. Step-wise multiple regression analysis was used to isolate the most important predictor variables of peak VO 2 from a set of measurements of PF: lung volumes, diffusion capacity, airway resistance, and maximum inspiratory and expiratory pressures; gas exchange: minute ventilation (V E ), tidal volume (V T ), respiratory exchange ratio (RER = carbon dioxide output divided by VO 2 ); and hemodynamics (HR, stroke index (SI) = stroke volume/body surface area, and mean arterial pressure). These measurements were made at rest and during submaximal exercise. Results: Using the set of PF variables (expressed as percentages of predicted). FEV, explained 30% of the variance of peak VO 2 . No other PF variables were predictive. After addition of resting hemodynamic data, SI was included in the prediction equation, raising the predictability to 40%, At the 60-W exercise level, 48% of the variance in peak VO 2 could be explained by SI and FEV 1 . At 150 W, the prediction increased to 81%. At this level VCO 2 /VO 2 (RER) also entered the prediction equation of peak VO 2 : 6.44.FEV 1 (%) + 13.0.SI - 1921.RER + 2380 (SE = 142 mL.min -1 .m 2 , P < 0.0001). Leaving out the gas exchange variable RER, maximally 64% of the variance in peak VO 2 could he explained. Conclusion: In conclusion, inclusion of pulmonary function and hemodynamic measurements could improve the prediction accuracy of a submaximal exercise test. The submaximal exercise test should be performed until a level of 150 W is reached. Noninvasive stroke volume measurements by means of EIC have additional value to measurement of HR alone. Finally, measurement of gas exchange significantly improves the predictability of peak VO 2 .