The effect of training status on the associations between aortic reservoir pressure and left ventricular untwisting rate.

Abstract

Athletic training status is known to influence cardiac function, although the mechanisms causing the changes are currently unknown. It is known that changes in arterial function can lead to cardiac adaptation and that trained individuals have a greater arterial desaturation in conditions of reduced oxygen availability. To help explain the influence of training status on cardiac function, this study aimed to investigate the associations between peak left ventricular (LV) untwisting rate and aortic reservoir pressure (RP) in normoxic and hypoxic conditions. The LV mechanics and aortic haemodynamics of 13 untrained males and 8 highly trained males (VO2peak: 36.4 ± 6.4 vs. 46.2 ± 6.1 ml.min.Kg-1) were assessed at rest and during sub-maximal exercise at 30, 40 and 50% of peak power output in normoxic (FiO2 = ~20.9%) and hypoxic conditions (FiO2 = ~12.0%). Trained individuals had a significantly higher aortic RP integral, a consistently lower sphericity index (repeated measures ANOVA: all P ≤ 0.05), and similar LV untwisting rates during both normoxic and hypoxic sub-maximal exercise (P > 0.05). Additionally, LV untwisting rate was significantly associated with aortic RP in trained individuals in normoxia and untrained individuals in hypoxia only (r2 = 0.37 and 0.12, respectively; both P ≤ 0.01). In conclusion, training status impacts on the associations between LV untwisting rate and aortic haemodynamic function, and the increased aortic reservoir function seen in trained individuals may play a role in facilitating a greater distribution of blood flow to the coronary arteries.