Objectives: To explore the influence of aerobic fitness (VO_{2 max}) on the relationship between left ventricular (LV) twist and vascular augmentation index (AIx) in young healthy individuals.

Background: Systolic LV twist and central vascular wave reflection (AIx) likely interact, however, the relationship between LV twist and AIx is not known. We hypothesised that the lower LV twist previously shown in endurance athletes with high VO_{2 max} would be associated with a lower AIx. Methods: 28 healthy males (21±2 yrs) were split into a moderate and high aerobic fitness group (VO_{2 max}: 49.0±4.9 and 62.7±6.8 ml/kg/min, respectively, p<0.0001). Heart rate, blood pressure, LV twist and AIx were assessed at rest and during exercise (40% of peak power). Differences in dependent variables between both groups were determined with two-way ANOVA. Relationships between LV twist and AIx were identified using Pearson’s product moment correlation.

Results: Heart rate and blood pressure did not differ between the two groups at rest or during exercise (p>0.05). While LV twist and AIx were significantly related in both the moderate and high fitness group (r²: 0.31 and 0.44, respectively, p<0.01), the high VO_{2 max} group had a significantly lower LV twist for the same AIx (p<0.001, see figure).

Conclusions: In young healthy individuals, LV twist and AIx are significantly related. However, the lower LV twist in individuals with high aerobic fitness cannot be explained by AIx, heart rate or blood pressure and, therefore, may indicate a previously unknown component of LV adaptation related to aerobic fitness.