Effect of 8-week HIIT and CMT on end-systolic, end-diastolic, relative wall thickness of left ventricle, and aerobic power among sedentary men

Recently, high intensity interval training (HIIT) and continuous moderate training (CMT) have been of interest in fields of exercise physiology and cardiovascular health. The aim of the present study was to compare the effect of 8-week HIIT and CMT on left ventricular end diastolic diameter (LVEDd) and end systolic diameter (LVEDs), and ventricular relative wall thickness (RWT) and aerobic power among inactive men.

For this purpose, 21 sedentary men (78.6 ± 2.1 kg, height: 175.5 ± 1.8 cm, age: 25 ± 1.21 years) participated in this study. Subjects were divided into control (CON), HIIT and CMT groups. CMT (constant load was 2 watts.kg-1) and HIIT (30 seconds with a load of 3.6 watts.kg-1body weight and 120 seconds with 1.4 watts.kg-1body weight) performed isocaloric training protocols for 8 weeks (on stationary bike). Echocardiography and Vo2max tests were performed before and after protocols. Collected data were analyzed after normality examination (Wilk-Shapiro). One-way ANOVA was used for further analysis.

Our findings showed that LVEDd in HIIT significantly increases when compared with CON (P = 0.03) after training. LVEDs in CMT significantly increased when compared with HIIT (P = 0.04) and CON (P = 0.02). RWT in both HIITand CMT was significantly higher than CON (P = 0.03 and P = 0.04, respectively). Vo2max in both groups significantly increased when compared with CON (P = 0.03 and P = 0.04, respectively).

It is suggested that HIIT may play protective role indecreasing myocardial workload through increasing LVEDd and venous return in inactive men.