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

Abstract

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 recent finding be extrapolated to the 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% ♀) 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 O₂ consumption (VO_2peak) 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 VO_2peak (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 O₂ 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 capacity to deliver and consume O₂ in HC adults irrespective of sex.

Keywords: Aerobic capacity; Body composition; Cardiovascular structure/function; Hans Chinese; Lean body mass; O2 extraction.

Figure 1

Frequency distribution of total lean body mass (LBM) in Hans Chinese (HC) women and men. LBM data (X axis) are grouped within intervals of equal width (2 kg).

Figure 2

Relationship of total lean body mass (LBM) with left ventricular structure and stiffness in Hans Chinese (HC) women and men. Each graph includes the lines of best fit (95% confidence interval). Women and men are represented by triangles and circles, respectively. LV Ea, left ventricular‐arterial elastance; LV Ed, left ventricular diastolic elastance; LV Ees, left ventricular end‐systolic elastance; LVIDd, left ventricular internal diameter at end‐diastole; LV_mass, left ventricular mass.

Figure 3

Relationship of total lean body mass (LBM) with left ventricular volumes at rest and peak exercise in Hans Chinese (HC) women and men. Each graph includes the lines of best fit (95% confidence interval). Women and men are represented by triangles and circles, respectively. LVEDV_peak, left ventricular end‐diastolic volume at peak exercise; LVEDV_rest, left ventricular end‐diastolic volume at supine rest; SV_peak, left ventricular stroke volume at peak exercise. SV_rest, left ventricular stroke volume at supine rest.

Figure 4

Relationship of total lean body mass (LBM) with the Fick principle components in Hans Chinese (HC) women and men. Each graph includes the lines of best fit (95% confidence interval). Women and men are represented by triangles and circles, respectively. A‐vO_2diffpeak, arteriovenous O₂ difference at peak exercise; Q_peak, cardiac output at peak exercise; VO_2peak, peak O₂ consumption.

Figure 5

Illustrative synopsis of the relationship of total lean body mass (LBM) with the cardiac and aerobic phenotype in Hans Chinese (HC) women and men. A‐vO_2diff, arteriovenous O₂ difference; LV, left ventricle; VO₂, O₂ consumption.