Supporting data for ''Cardiac-Hematological Capacity in Healthy Hans Chinese: Effects of Blood Volume and Body Composition''

Cardiac output (Q) is essential to the assessment of cardiac function and the diagnosis of various heart diseases. Peak cardiac output (Q_peak) elicited by incremental exercise to peak effort, represents cardiac capacity. Q_peak strongly predicts maximal oxygen uptake (VO_2max) as well as mortality. Endurance training induces significant increases in VO_2max. Despite of similar exercise stimuli, women tend to improve less in cardiovascular adaptations compared with men. One possible reason is that women have smaller heart compared with men and the pericardium may limit the expansion of the left ventricle (LV) during peak exercise, thus the cardiac adaptation is limited. In chapter 1, the ambient pressure driving venous return during incremental exercise was manipulated in women and men, revealing that the female young heart is unrestrained by venous return or structural factors external to the myocardium.

Blood volume (BV) facilitates venous return, cardiac filling and output, determining aerobic capacity. Despite women are endowed with lower blood-oxygen carrying capacity, women and men presented similar VO_2max after normalization by lean body mass (LBM). LBM is strongly and exclusively associated with aerobic capacity in women, independent of body fat percentage. In chapter 2, whether aerobic capacity and its biological determinants including blood volume and body composition are ethnic-specific were investigated in a well-characterized corhort of Hans Chinese (HC) and European-American (EA) individuals.

LBM and the functional capacity of the cardiovascular system constitute a female-specific relationship in EA individuals. In chapter 3, whether such finding can be extrapolated to HC, a population characterized by low LBM was explored. Overall, this study eliminated the knowledge gaps in contemporary human physiology regarding main determinants of cardiorespiratory fitness, potentially translating to improve or preserve cardiovascular health in a large fraction of the population.