Reference equations for peak oxygen uptake during cycle ergometry based on body composition estimates

To derive sex-specific peak oxygen uptake (VO₂peak) reference equations for cycle ergometer cardiopulmonary exercise testing (CPET) that integrate estimations of lean body mass (eLBM) and body fat percentage (eBF) based on sex, age, height and weight.

We pooled data from apparently healthy adults who performed cycle ergometry in Belgium (FLEMENGHO and iCOMPEER cohorts) and the USA (FRIEND registry). Per subgroup of sex, age and body mass index (BMI), 70% of the data was used for training the equations and 30% for testing them.

The cohort consisted of 1778 females and 1243 males. For females, the mean age was 49.8±13.3 years, BMI 27.1±4.9 kg·m^-2 and VO₂peak 1488.4±360.3 mL·min^-1. For males, the mean age was 50.2±13.3 years, BMI 27.6±4.0 kg·m^-2 and VO₂peak 2467.1±595.5 mL·min^-1. The reference equation for females was $\begin{array}{c}V{O}_{2peak,females}\left[mL\times {min}^{-1}\right]\\ =1335.9+31.3\times eLBM\left(kg\right)\\ -21.8\times eBF\left(\%\right)-0.119\times {age}^2\end{array}$ .In the test set, the SE of VO₂peak estimates (SEE) was 279.9 mL·min^-1. For males, the equation was $\begin{array}{c}V{O}_{2peak,males}\left[mL\times {min}^{-1}\right]\\ =2264.4+42.5\times eLBM\left(kg\right)\\ -71.2\times eBF\left(\%\right)-0.134\times {age}^2\end{array}$ .In the test set, SEE=434.2 mL·min^-1. Per cent-predicted VO₂peak calculated with the proposed equations presented a good calibration among subgroups.

The proposed equations allowed calibrated comparisons of an individual's VO₂peak to that of healthy individuals matched by sex, age and estimated body composition.