Objective: Exercise training has been known to cause structural and functional alterations in the heart called athletes heart. We aimed to investigate the effects of incremental endurance exercise training (IEET) on the left ventricular (LV) mechanics in healthy subjects.
Methods: This prospective observational study included 34 healthy young men who participated in competitive sports. The participants were subjected to a six-month IEET program. The LV mechanics measured using two-dimensional speckle tracking echocardiography was recorded while the participants were in an inactive state before and at the end of the six months. To compare continuous variables before and after IEET, Wilcoxon or paired-t test were used.
Results: Baseline and post training echocardiographic measurements showed that there was no significant change in LV ejection fraction (%) (p=0.64) and there were an increase in end-systolic and end-diastolic diameters, posterior and septal wall thickness, relative wall thickness and LV mass index (p<0.05, for all). LV mechanical parameters such as global strain (S) (19.8±1.33% vs. 20.4±1.26%, p=0.001), apical four -chamber S (19.4±1.96% vs. 20.1±1.86%, p=0.01), apical two- chamber S (19.9±1.75% vs. 20.7±1.75%, p=0.003), apical (23.0±3.1% vs. 23.6±3.2%, p=0.03), and basal circumferential S (21.1±2.2 % vs. 21.6±2.5%, p=0.03), and apical rotation (degree) (7.9±0.95 vs. 8.4±0.74, p=0.001) values were significantly increased by IEET.
Conclusion: We demonstrated that IEET has led to exercise related cardiac structural and functional changes such as LV dilatation and LV hypertrophy, accompanied by a significant increase in LV systolic S and LV twist measurements.