The effects of HIIT compared to MICT on endothelial function and hemodynamics in postmenopausal females

The study was designed to investigate the role of exercise in ameliorating endothelial function and hemodynamics in postmenopausal females, and compare the different effects of high-intensity interval training and moderate-intensity continuous training by equalizing training load.

Randomized controlled trial.

First intervention, 30 volunteers were randomized into low-intensity continuous training group or sedentary group. The low-intensity continuous training group was assigned to a 12-week training program at an intensity of 40% maximum heart reserve. The second intervention was an 8-week training program, in which 18 individuals were randomly placed either in the moderate-intensity continuous training or high-intensity interval training group. Flow-mediated dilatation, blood samples, carotid ultrasound, and wall shear stress were collected before, during, and after the interventions.

Flow-mediated dilatation was significantly increased in low-intensity continuous training group (p = 0.02), moderate-intensity continuous training (p = 0.023) and high-intensity interval training (p < 0.01) groups, with a time × group interaction for %FMD (F_{2, 32} = 4.421, p = 0.02), and a main effect of time (F_{2, 32} = 27.658, p < 0.001). Nitric oxide in low-intensity continuous training increased remarkably (p = 0.024) and was higher than that in control (p = 0.011). High-intensity interval training (p < 0.001) and moderate-intensity continuous training (p < 0.001) increased nitric oxide. Endothelin was decreased only in high-intensity interval training group (p = 0.049). All the training programs had a remarkable impact on wall shear stress.

Low-intensity continuous training can improve endothelial function in postmenopausal females. High-intensity interval training could be an effective training regimen for improving endothelial function than moderate-intensity continuous training in postmenopausal females.