Abstract 1381: Importance of Cardiac Size on Aerobic Fitness in Young Healthy Children
Introduction. Aerobic fitness, defined as maximum oxygen uptake (VO2PEAK), is generally considered to be the best single marker for the functional capacity of the cardio-respiratory system. Low aerobic fitness has, in adults, been shown to be a strong predictor for a variety of diseases and all causes of death. It is therefore of interest to study how various factors affect VO2PEAK, also in childhood.
Hypothesis. We assessed the hypothesis if cardiac size is of importance for VO2PEAK in young healthy children.
Methods. Cross-sectional study of 245 (137 boys and 108 girls) children aged 8–11 years, recruited from a population-based cohort. Total lean body mass (LBM) and total fat mass (TBF) were measured by Dual-energy x-ray absorptiometry. VO2PEAK was assessed by indirect calorimetry during maximal exercise test, and maximal heart rate (Max HR) was recorded. Echocardiography, 2-dimensional guided M-mode, was performed in accordance with ASE-guidelines. Left ventricular end-diastolic diameter (LVDD) and left atrial end-systolic diameter (LA) were measured. Maturity evaluated according to Tanner.
Results. Univariate correlations, with adjustment for sex, between VO2PEAK versus LVDD (r=0.43, P<0.05) and LA (r=0.31, P<0.05). Multiple regression analysis with VO2PEAK as dependent variable and inclusion of LBM, TBF, LVDD, LA, Sex, Age, Tanner, and Max HR as independent variables concluded that both LVDD and LA were independently related to VO2PEAK. Most important factor for the model was LBM and Max HR, which combined explained 62% of the variance in VO2PEAK. Sex explained an additional 3%, and both LVDD and LA only 1% each.
Conclusion. Findings from this population-based cohort of young healthy children show that cardiac size is of minor importance for VO2PEAK.