Effects of Aerobic Interval and Moderate Continuous Training on Left Ventricular Mechanics in Sedentary Men

Abstract

Improved myocardial contractility is a critical circulatory adaptation to aerobic exercise training. What kind of the exercise strategy that enhances contractility efficiency in heart has not yet been established. This study investigated how aerobic interval (AIT) and moderate continuous training (MCT) influence the left ventricular (LV) mechanics in sedentary men. Thirty‐six sedentary males were randomized to perform AIT (3‐minute intervals at 40% and 80% VO2max, n=18) or MCT (sustained 60% VO2max, n=18) for 30 minutes/day, 5 days/week for 6 weeks. LV mechanics were measured by two‐dimensional and speckle tracking echocardiography at normoxic (21% of FIO2) and hypoxic (12% of FIO2) environments. The experimental results demonstrated that AIT exhibited higher enhancement of cardiac output and VO2 at peak performance, compared to MCT did. Moreover, the AIT group also had higher increases in LV mass and stroke volume than the MCT group. In LV contractile efficiency, AIT, rather than MCT, significantly decreased apex rotation to reduce degree of torsion and simultaneously increased circumferential strain of mitral valve segmentation under normoxic and hypoxic conditions.Hence, we conclude that AIT is superior to MCT for enhancing aerobic capacity. Moreover, AIT effectively improves LV mechanics by increasing contractile efficiency at normoxic and hypoxic environments in sedentary men.