Resumen de Methods to Estimate V[spacing dot above]O2max upon Acute Hypoxia Exposure.
Martin J. MacInnis, Keith R. Lohse, Sean F. Nugent, Kristin E. MacLeod
AB Introduction: Altitude and an individual's V[spacing dot above]O2max contribute to a decrease in V[spacing dot above]O2max under hypoxic conditions. The purpose of this study was to update previous reviews with recent research in order to quantitatively determine the individual and interacting effects of altitude and baseline V[spacing dot above]O2max on V[spacing dot above]O2max upon acute exposure to hypoxia while developing a statistical model to predict an individual's V[spacing dot above]O2max under hypoxic conditions. Methods: Meta-regression was conducted on 105 independent groups of participants (n = 958 subjects from 80 different studies). A series of regression models was tested. The final model included altitude, baseline V[spacing dot above]O2max, Alt2, baseline V[spacing dot above]O2max2, and the interaction of altitude with baseline V[spacing dot above]O2max. Results: A curvilinear model provided the best fit for metadata, explaining almost 80% of the variance in the null model. Nonlinear effects of Alt2 ([beta] = -0.078; 95% confidence interval, -0.15 to -0.002) and baseline V[spacing dot above]O2max2 ([beta] = -0.003; 95% confidence interval, -0.004 to -0.001) showed that V[spacing dot above]O2max decreases as altitude increases and that the decrease is greater in individuals with higher aerobic capacities. The interaction of these effects ([beta] = -0.028; 95% confidence interval, -0.042 to -0.015) also showed that the effects of altitude were augmented with higher baseline aerobic capacities. Furthermore, the predictions of the model were fairly accurate in predicting individual decreases in V[spacing dot above]O2max (root-mean-squared error, 3.9 mL[middle dot]kg-1[middle dot]min-1). Conclusions: These data provide a robust quantitative framework for the curvilinear and interacting effects of altitude and baseline V[spacing dot above]O2max in determining an individual's effective V[spacing dot above]O2max at altitude. This predictive model is useful for a priori power calculations, design of future experimental studies, and prediction of aerobic capacity declines in applied settings
