Lean body mass and the cardiorespiratory phenotype: An ethnic-specific relationship in Hans Chinese women and men

Background Lean body mass (LBM) and the functional capacity of cardiovascular (CV) and respiratory systems constitute a female-specific relationship in European-American individuals. Whether this recentfinding be extrapolated tothe world's largest ethnic group, that is, Hans Chinese (HC, a population characterized by low LBM), is unknown. Methods Healthy HC adults (n=144,50%female) closely matched by sex, age and physical activity were included. Total and regional (leg, arm and trunk) LBM and body composition were measured via dual-energy X-ray absorptiometry. Cardiac structure, stiffness, central/peripheral haemodynamics and peak O(2 )consumption (VO2peak) were assessed via transthoracic echocardiography and pulmonary gas analyses at rest and during exercise up to peak effort. Regression analyses determined the sex-specific relationship of LBM with cardiac and aerobic phenotypes. Results Total and regional LBM were lower and body fat percentage higher in women compared with men(P<0.001). In both sexes, total LBM positively associated with left ventricular (LV) mass and peak volumes(r >= 0.33,P <= 0.005) and negatively with LV end-systolic and central arterial stiffness (r >= 0.34,P <= 0.004). Total LBM strongly associated with VO2peak(r >= 0.60,P<0.001) and peak cardiac output (r >= 0.40,P<0.001) in women and men. Among regional LBM, leg LBM prominently associated with the arterio-venous O(2 )difference at peak exercise in both sexes (r >= 0.43,P<0.001). Adjustment by adiposity or CV risk factors did not modify the results. Conclusions LBM independently determines internal cardiac dimensions, ventricular mass, distensibility and the ca-pacity to deliver and consume O2in HC adults irrespective of sex.