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

Purpose: Many attempts have been made to predict peak 902 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 (V) over dotO(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) over dot(E)), tidal volume ((V) over dot(T)), respiratory exchange ratio (RER = carbon dioxide output divided by ((V)over dotO(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), FEV1 explained 30% of the variance of peak (V) over dotO(2). No Ether 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 (V) over dotO(2), could be explained by SI and FEV1. At 150 W, the prediction increased to 81%. At this level (V) over dotCO(2)/(V) over dotO(2) (RER) also entered the prediction equation of peak (V) over dotO(2): 6.44.FEV1(%) + 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 (V) over dotO(2) could be 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 (V) over dotO(2).