Skeletal muscle mass is a strong predictor of cardiorespiratory fitness in the Chinese population with obesity.

ABSTRACT

BACKGROUND AND AIMS: Although skeletal muscle is well-known as physiologically related to VO2max, the independent predictive value of skeletal muscle mass (SMM) VO2max in people with obesity has not been studied. This study aims to determine the relationships between maximal oxygen uptake (VO2max) and SMM in the Chinese population with obesity. METHODS AND RESULTS: Overall, 409 participants with obesity were included in this cross-sectional study. A maximal and graded exercise testing measured VO2max, and body compositions were measured by bioelectrical impedance analysis. Subsequently, correlation coefficients and stepwise multiple linear regression analyses were used to determine the relationships between VO2max and body compositions. SMM was found to have a significant correlation with VO2max (r = 0.290, P < 0.001) after adjusting for sex, age, body mass index (BMI), waist-to-hip ratio, and percent body fat (PBF). In previous studies, BMI was widely recognized as a strong predictor of VO2max. This study revealed surprising results: after SMM was controlled, the correlation between BMI and VO2max was reduced (from r = 0.381, P < 0.001 to r = 0.191, P < 0.001). SMM was found the most important independent predictor. In the regression model, the variance of VO2max was explained by the SMM which accounted for 27.4%. CONCLUSIONS: In summary, SMM is a stronger independent predictor of cardiorespiratory fitness in the Chinese population with obesity than sex, age, BMI, waist-to-hip ratio, and PBF.