Background: Correction for body composition is recommended for appropriate interpretation of equivocally altered cardiac dimensions. We sought to investigate the impact of body composition on athletes' heart.
Methods: Left ventricular mass (LVM), septal wall thickness (SWT) and end-diastolic diameter (LVEDD) were measured by echocardiography in 1051 elite athletes (26% female, aged 18-40 years) and in 338 sedentary controls matched for age, gender and body size. Body fat was determined by skinfold thickness measurements.
Results: Normative ranges are provided for LVM, LVEDD and SWT scaled to body surface area (BSA), height, height(2.7) and fat-free mass (FFM). The strongest correlation was found for FFM (r = 0.70; 0.64; 0.49; p < 0.001 each). LVM, LVEDD and SWT differed significantly (p < 0.05) between athletes of low, moderate and high dynamic disciplines. Correcting LVEDD for height(2.7) eliminated these differences (p > 0.05), whereas LVM and SWT remained significantly increased in high dynamic athletes despite correction for body size. Gender differences were consistently eliminated by scaling LVEDD to FFM(0.33) and SWT to BSA, but scaled LVM remained significantly increased in male athletes. Compared to sedentary controls, significant differences in LVEDD and SWT disappeared after correction for height(2.7) and FFM, but LVM again remained significantly higher in athletes.
Conclusions: Adaptation of left ventricular dimensions to exercise training is closely related to body composition, in particular to FFM. The normative ranges for LVEDD, SWT and LVM scaled to body size aid interpretation of equivocal alterations in elite athletes. However, the increase of LVM in particular reveals exercise-induced adaptations beyond these associations.