Is a verification phase useful for confirming maximal oxygen uptake in apparently healthy adults? A systematic review and meta-analysis

Abstract

Background The ‘verification phase’ has emerged as a supplementary procedure to traditional maximal oxygen uptake (VO2max) criteria to confirm that the highest possible VO2 has been attained during a cardiopulmonary exercise test (CPET). Objective To compare the highest VO2 responses observed in different verification phase procedures with their preceding CPET for confirmation that VO2max was likely attained. Methods MEDLINE (accessed through PubMed), Web of Science, SPORTDiscus, and Cochrane (accessed through Wiley) were searched for relevant studies that involved apparently healthy adults, VO2max determination by indirect calorimetry, and a CPET on a cycle ergometer or treadmill that incorporated an appended verification phase. RevMan 5.3 software was used to analyze the pooled effect of the CPET and verification phase on the highest mean VO2. Meta-analysis effect size calculations incorporated random-effects assumptions due to the diversity of experimental protocols employed. I2 was calculated to determine the heterogeneity of VO2 responses, and a funnel plot was used to check the risk of bias, within the mean VO2 responses from the primary studies. Subgroup analyses were used to test the moderator effects of sex, cardiorespiratory fitness, exercise modality, CPET protocol, and verification phase protocol. Results Eighty studies were included in the systematic review (total sample of 1,680 participants; 473 women; age 19–68 yr.; VO2max 3.3 ± 1.4 L/min or 46.9 ± 12.1 mL·kg-1·min-1). The highest mean VO2 values attained in the CPET and verification phase were similar in the 54 studies that were meta-analyzed (mean difference = 0.03 [95% CI = -0.01 to 0.06] L/min, P = 0.15). Furthermore, the difference between the CPET and verification phase was not affected by any of the potential moderators such as verification phase intensity (P = 0.11), type of recovery utilized (P = 0.36), VO2max verification criterion adoption (P = 0.29), same or alternate day verification procedure (P = 0.21), verification-phase duration (P = 0.35), or even according to sex, cardiorespiratory fitness level, exercise modality, and CPET protocol (P = 0.18 to P = 0.71). The funnel plot indicated that there was no significant publication bias. Conclusions The verification phase seems a robust procedure to confirm that the highest possible VO2 has been attained during a ramp or continuous step-incremented CPET. However, given the high concordance between the highest mean VO2 achieved in the CPET and verification phase, findings from the current study would question its necessity in all testing circumstances. PROSPERO Registration ID CRD42019123540.

Utility of Verification Testing to Confirm Attainment of Maximal Oxygen Uptake in Unhealthy Participants: A Perspective Review

“…Our review corroborates results from healthy, fit adults [ 17 , 36 ] showing no difference in HRmax between GXT and VER. However, a subset of data presented in this study [ 36 ] from participants with average cardiorespiratory fitness, exhibited significantly lower HRmax (−3 b/min) in response to VER compared to GXT.…”

“…Our review ( Table 2 ) shows durations as brief as 2–5 min between protocols [ 24 , 25 , 27 , 30 , 31 ], 5–15 min [ 13 , 14 , 15 , 22 , 24 , 28 , 32 , 33 ], to as long as several days between protocols [ 10 , 27 ]. A recent systematic review [ 17 ] concluded that there was no effect of recovery interval on the difference in VO 2 max between protocols, which would suggest that any duration is appropriate. It is also apparent that some studies require an active recovery between protocols [ 13 , 15 , 23 , 31 ], whereas a passive recovery is completed in other investigations [ 11 , 14 , 22 , 25 , 29 , 32 ].…”

“…In addition, data show its efficacy to confirm attainment of VO 2 max in adults with metabolic syndrome [ 15 ] as well as heart failure [ 16 ]. Recent data also show that implementing VER reveals more precise determinants of increases in VO 2 max in response to high intensity interval training in adults with metabolic syndrome compared to graded exercise testing [ 17 ]. So, similar to healthy adults, use of VER seems warranted to confirm attainment of ‘true’ VO 2 max in persons with chronic disease.…”

“…In addition, VO 2 max is frequently measured as a primary outcome in exercise training studies due to its strong relationship with health status [ 1 ]. Moreno-Cabanas et al [ 17 ] concluded that ramp testing misrepresents the training-induced change in VO 2 max in a majority of individuals with metabolic syndrome, and they emphasized the necessity of VER to better represent the VO 2 max response to training. However, to our knowledge, no review article has summarized efficacy of VER to confirm VO 2 max incidence in unhealthy participants.…”

Comparison of constant load exercise intensity for verification of maximal oxygen uptake following a graded exercise test in older adults

“…More recently, the use of a secondary constant load test that is performed following a graded exercise test has been implemented as a strategy to verify a maximal effort and VO 2 max (Costa et al, 2021 ; Midgley & Carroll, 2009 ; Poole et al, 2008 ). While the use of a constant load test to verify VO 2 max has gained consideration, the intensity at which these constant load tests have been performed is variable.…”