Abstract
Endurance-trained athletes with higher aerobic power (Vo_2max) have a large-sized left ventricle (LV) and aorta (Ao). We therefore hypothesized that the individual variability of Vo_2ax can be estimated using resting LV and Ao dimensions. In looking at this question we performed a laboratory-based cross-sectional study to determine the relationship between Vo_2max, LV dimensions, and Ao dimensions in young subjects with wide ranges of physical activity status. One hundred forty-two healthy young men (20-35 years), who were either sedentary, recreationally active or endurance-trained, participated in the cross-sectional study. Subsequently, a meta-analysis approach was used to collect 28 studies involving 58 groups and 816 subjects. LV and Ao dimensions were determined by echocardiography at supine rest. In the cross-sectional study and meta-analysis, LV end-diastolic diameter (LVEDD) and end-systolic diameter (LVESD), posterior wall thickness (PWT) and inter-ventricular septum thickness (IVST), and Ao diameter (AoD) were positively and significantly correlated with Vo,max. When we performed a stepwise regression analysis in the cross-sectional study to determine independent predictors of Vo_2max, the variables entered were LVEDD, AoD, and PWT, which together explained 60-70% of the variability. Furthermore, we attempted to develop equations for predicting Vo_2max. Multiple regression analyses using LVEDD, AoD, and PWT as the explanatory variables for predicting Vo2max yielded the following equations. Vo_2max (ml・min^<-1>・kg^<-1>) = 49.2 LVEDD (mm/kg) + 27.2 AoD (mm/kg) + 43.9 IVST (mm/kg) -2.6. These results suggest that the variability of Vo_2max can be accounted for by differences in both left ventricular and aortic structure. Furthermore, echocardiography at supine-rest was useful for evaluating maximal aerobic power, specifically for young healthy men, who demonstrated a wide range of trained states.
