Purpose: The present cross-sectional study aimed to investigate whether a maximal oxygen uptake (VO2max) verification phase (VER) could improve the accuracy of a previous graded exercise test (GXT) to assess individual VO2max in hypertensive individuals.
Methods: Thirtythree older adults with hypertension (24 women) taking part in the Hypertension Approaches in the Elderly Study (NCT03264443) were recruited. Briefly, after performing a treadmill GXT to exhaustion, participants rested for 10 min and underwent a multistage VER to confirm GXT results. Individual VO2max, respiratory exchange ratio (RER), maximal heart rate (HRmax), and rating of perceived exertion (RPE) were measured during both GXT and VER tests. Mean values were compared between bouts using paired sample t-tests and VO2max was also compared between GXT and VER on an individual basis.
Results: Testing was well tolerated by all participants. Both absolute (p=0.011) and relative (p=0.014) VO2max values were higher in VER than in GXT. RER (p<0.001) and RPE (p=0.002) were lower in VER, whereas HRmax (p=0.286) was not different between the two trials. Individual VO2max comparisons revealed that 54.6% of the participants (18/33) achieved a VO2max value that was ≥3% during VER (mean: 13.5%, range: from +3% to +22.1%, ES=0.062), whereas 87.9% (29/33) of the tests would have been validated as a maximal effort if the classic criteria were employed (i.e. VO2 plateau or at least two secondary criteria).
Conclusion: In sedentary older individuals with hypertension, GXT to exhaustion underestimated VO2max in more than half of tested participants, even when established but criticized criteria were used to confirm whether a maximal effort was attained. Employing VER after GXT is a quick approach to assist with the verification of an individual’s VO2max.