Metabolic equivalent concept in apparently healthy men: A re-examination of the standard oxygen uptake value of 3.5 mL·kg-1·min-1

This study compared resting oxygen uptake (V̇O2) with the standard metabolic equivalent (MET) value of 3.5 mL·kg(-1)·min(-1), tested the accuracy of a previously published prediction model for resting V̇O2, and proposed a new prediction model for a more homogeneous population. One hundred and twenty-five apparently healthy men, aged 17-38 years, visited the laboratory for the assessment of resting V̇O2. The mean resting V̇O2 of 3.21 mL·kg(-1)·min(-1) (95% confidence interval (CI), 3.13 to 3.30) was significantly lower than the standard MET value of 3.5 mL·kg(-1)·min(-1) (mean difference, 0.29; 95% CI, 0.20 to 0.37; t = 6.7; p < 0.001). The prediction model proposed by a previous study, derived from a heterogeneous sample, exhibited no predictive ability in our more homogeneous sample. However, our population-specific regression model, which included body surface area and percent body fat as predictors, demonstrated relatively poor predictive ability, with a low R(2) (0.22) and high standard error of the estimate (0.42 mL·kg(-1)·min(-1)). Pearson's correlation coefficients for body surface area and resting V̇O2, and for percent body fat and resting V̇O2, were 0.20 (p = 0.022) and -0.36 (p < 0.001), respectively. In conclusion, the standard MET value of 3.5 mL·kg(-1)·min(-1) considerably overestimates mean resting V̇O2 in a relatively large group of apparently healthy men. Our population-specific prediction model for resting V̇O2 demonstrated relatively poor accuracy, although it was considerably more accurate than the previously published model. Further research needs to be conducted to establish accurate population-specific prediction models.