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Date of Graduation
Master of Science (MS)
Nicholas D. Luden
Mike J. Saunders
Christopher J. Womack
Purpose: The objective of this study was to determine the utility of including a verification stage when assessing maximum oxygen consumption (VO2max) in normobaric hypoxia (i.e., simulated high altitude), compared to sea level. A secondary aim was to assess the efficacy of primary and secondary criteria (VO2 plateau, RER, maximum heart rate) traditionally used to confirm the attainment of VO2max during the graded exercise test (GXT), in both normoxia and hypoxia. Methods: Twenty male (n=15) and female (n=5) subjects completed two separate cycling VO2max trials, each consisting of a traditional GXT and a verification stage, separated by 10 min of passive rest. Each subject completed a test in normoxia and another in hypoxia, separated by ≥ 48 h and completed in a randomly counterbalanced order. The highest VO2 aggregate over 30 s was used as the VO2max value from each stage and condition (normoxic GXT, normoxic verification, hypoxic GXT, and hypoxic verification). Expired air was continuously collected and analyzed with a ParvoMedics metabolic cart. Data were analyzed using a series of repeated-measures ANOVAs. Results: VO2max was higher in normoxia compared to hypoxia (p < 0.05), with no significant differences between stages (GXT vs. verification) within each condition. However, when using a threshold “meaningful effect” of 2% (i.e., 2% higher VO2 attained in verification vs. GXT), 12 of 20 subjects exhibited higher values during the verification stage in normoxia, whereas only 3 of 20 subjects had higher VO2max values during the verification stage in hypoxia. Based on sensitivity and specificity calculations, primary (plateau < 150 mL/min increase in VO2 with an increase in workload) and secondary criteria (peak HR within ± 10 bpm of age-predicted HR max and RER ≥ 1.10) were unable to verify VO2max attainment in the GXT. Conclusion: While we did not observe a stage x condition interaction, there appeared to be a meaningful difference in the proportion of subjects that achieved substantially (> 2%) higher values during verification vs. GXT in normoxia vs. the proportion of like subjects in hypoxia. Furthermore, the primary and secondary criteria from the GXT were inadequate at confirming a true VO2max during the GXT. Altogether, the utility of including a verification stage when VO2max testing appears to possess more utility when testing in normoxia vs. hypoxia.
Roenker, Brittany, "Utility of Including a Verification Stage When VO2max Testing in Normobaric Hypoxia" (2023). Masters Theses, 2020-current. 203.
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