A reference equation for peak oxygen uptake for cycle ergometry in Chinese adult participants

Accurately quantifying cardiorespiratory fitness (CRF) through cardiopulmonary exercise testing (CPET) is increasingly important for improving risk assessment and guiding clinical decisions. However, research on V̇O₂peak reference values and predictive equations for the Chinese population remains limited. This study aimed to establish a V̇O₂peak predictive equation for Chinese adults. This study analyzed healthy participants who underwent CPET at Peking University Third Hospital (PUTH) from September 1, 2017, to September 1, 2023. Data from September 1, 2017, and August 31, 2021 were used as the derivation cohort, and September 1, 2021, to September 1, 2023 were utilized as an external validation cohort for temporal validation. The derivation cohort underwent backward multivariate regression analysis to generate the V̇O₂peak prediction equation, which was compared with the widely-used Wasserman, FRIEND and Xiangya equations. The PUTH derivation cohort (N = 4531, mean age: 50.7 years, 18-88 years) and validation cohort (N = 4624, mean age: 46.1 years, 18-89 years) included 48.8 and 48.5% men, respectively. With increasing age, both men and women V̇O₂peak exhibited a general decline. The predictive equation for V̇O₂peak was established based on the derivation cohort: V̇O₂peak (mL·min^-1) =  -24364.9 - 621.3 × Sex (Women = 1, Men = 2) -10.7 × Age + 0.2 × Height² (cm) + 6464.7 × Log(BMI) -24997.2 × Log(BSA) +12388.6 × Log(LBM) (adjusted R² = 0.624, p < 0.001). It demonstrated higher consistency between measured and predicted results compared to Xiangya, Wasserman, and FRIEND equations. This study presents the PUTH equation, a new V̇O₂peak prediction equation for Chinese adults. Compared to existing equations, the PUTH equation shows reduced bias and improved accuracy, providing a more reliable tool for assessing CRF and guiding clinical interventions in the Chinese population.