Abstract
An individual’s resting metabolic rate (RMR) is commonly the largest contributor to total daily energy expenditure. The accepted reference method for in vivo measurement of RMR is indirect calorimetry (IC). However, the accessibility of traditional IC analyzers is limited to select settings; therefore, portable indirect calorimeters are also applied to estimate RMR. Limited data are available to inform the validity of the VO2 Master for estimating RMR in muscular resistance-trained adults. PURPOSE: The purpose of this study was to determine the validity of the VO2 Master portable metabolic analyzer for estimating RMR in muscular resistance-trained adults. METHODS: A sample of 38 resistance-trained adults (15 F, 23 M; [mean ± SD] age 28.0 ± 7.9 y, height 172.0 ± 9.6 cm, weight 77.6 ± 12.9 kg, body fat% 17.5 ± 5.2, fat-free mass index 21.5 ± 2.9 kg/m2) underwent metabolic assessment via a metabolic cart (IC) and a portable metabolic analyzer (VO2 Master) in a single visit. RMR estimates obtained from IC were considered the reference values. Equivalence testing was used to evaluate whether the VO2 Master demonstrated equivalence with IC. Null hypothesis significance testing was also performed, and Bland-Altman analysis was used alongside linear regression to assess the degree of proportional bias. Constant error (CE), mean absolute error (MAE), and 95% limits of agreement (LOA) were also calculated. RESULTS: The mean ± SD RMR estimates for IC and the VO2 Master were 2192.7 ± 408.8 kcal/d and 1798.2 ± 418.8 kcal/d, respectively. The CE and MAE were -394.6 kcal/d and 419.1 kcal/d, respectively. Additionally, no proportional bias was observed, but wide LOA were present, and the VO2 Master did not demonstrate equivalence with IC. CONCLUSION: Given these findings, the consistent underestimation by the VO2 Master indicates that it may not be suitable for application in muscular resistance-trained adults. While noteworthy, fat-free mass contributes to a considerable portion of variance within RMR, and it has been suggested that the relationship between underprediction bias and RMR is likely a result of greater fat-free mass.
Recommended Citation
Rodriguez, Christian; Florez, Christine M.; Tinoco, Ethan; Cardoso, Joao P.; Rasco, Jaylynn; Whitson, Julia; Francis, Sieneh; and Tinsley, Grant M.
(2025)
"Validity of a Portable Metabolic Analyzer for Estimating Resting Metabolic Rate in Muscular Resistance-trained Adults,"
International Journal of Exercise Science: Conference Proceedings: Vol. 2:
Iss.
17, Article 54.
Available at:
https://digitalcommons.wku.edu/ijesab/vol2/iss17/54
