Importance of a verification test to accurately assess VO₂max in unfit individuals with obesity

Abstract

Background To determine the trustworthiness of graded exercise test to exhaustion (GXT) to assess maximal oxygen uptake ( ) in metabolic syndrome individuals with obesity and poor cardiorespiratory fitness. Methods was assessed in 100 metabolic syndrome adults (57 ± 8 years; 34% women), with obesity (BMI 32 ± 5 kg·m −2 ) using GXT followed by supramaximal constant‐load verification test (VerT) at 110% of maximal GXT work rate. data from GXT and VerT were compared using paired t test and plotted for Bland‐Altman analysis. GXT sensitivity and specificity to detect were also calculated. Results Seventy individuals did not achieve plateau during GXT. GXT underestimated in 40 subjects. In these subjects, the magnitude of underestimation with GXT was 9% (167 mLO 2 ·min −1 ; P < .001). In the whole sample (n = 100), bias error differences between GXT and VerT was 63 mLO 2 ·min −1 (3% underestimation). This error was constant regardless of differences in fitness levels among individuals ( R = −0.07; homoscedasticity). GXT results were unreliable in 62% of the sample with 16% of false‐positive and 46% of false‐negative results. Sensitivity and specificity of GTX to assess were low (ie, 23% and 60%, respectively). Conclusion Our data indicate that the magnitude (3%‐9%) and prevalence (40% of subjects) of underestimation with the use of a GXT alone is high in a large sample of unfit metabolic syndrome individuals with obesity. Our data advocate for the need of using VerT after GXT to avoid significant cardiorespiratory fitness underestimation in metabolic syndrome individuals with obesity and low fitness level.