Med Sci Sports Exerc. 2023 Jan 16. doi: 10.1249/MSS.0000000000003126. Online ahead of print.
ABSTRACT
PURPOSE: To assess the V̇O2 uptake obtained during a GXT and subsequent verification phase in untrained participants in a hot environment.
METHODS: Twelve sedentary males completed a GXT followed by a biphasic supramaximal-load verification phase in a hot environment (39 ° C, 32% relative humidity). Rest between tests occurred in a temperate chamber and lasted until gastrointestinal temperature returned to baseline.
RESULTS: Mean verification phase V̇O2max (37.8 ± 4.3 mL·kg-1·min-1) was lower than GXT (39.8 ± 4.1 mL·kg-1·min-1; p = 0.03) and not statistically equivalent. Using an individualized analysis approach, only 17% (2/12) of participants achieved a V̇O2 plateau during the GXT. Verification phase confirmed GXT V̇O2max in 100% of participants while the traditional and the new age dependent secondary V̇O2max criteria indicated GXT V̇O2max achievement at much lower rates (8/12 [67%] vs. 7/12 [58%], respectively). Correlational indices between GXT and verification phase V̇O2max were strong (ICC = 0.95; r = 0.86) and Bland-Altman analysis revealed a low mean bias of -2.1 ± 1.9 mL·kg-1·min-1 and 95% limits of agreement (-5.8 to 1.7 mL·kg-1·min-1).
CONCLUSIONS: Very few untrained males achieved a V̇O2 plateau during GXT in the heat. When conducting GXT in a hot condition, the verification phase remains a valuable addition to confirm V̇O2max in untrained males.
PMID:36719655 | DOI:10.1249/MSS.0000000000003126
