Effects of interval training on blood pressure and endothelial function in hypertensive patients

Abstract

Background Several studies have recently shown that high-intensity interval training (HIIT) is superior to moderate-intensity continuous exercise (MICE) for improvements on endothelial in patients with cardiovascular disease. However, little is known about its effects on changes in blood pressure, especially in hypertensive patients. Purpose To compare the effects of HIIT and MICE on changes in blood pressure reduction and endothelial function in hypertensive patients. Methods Fourteen hypertensive patients, aged 52.1±7.6, participated in this study. They tapered off their medications, if necessary, and were randomized to either HIIT (n = 7) or CME (n = 7) group. HIIT was composed of 5 sets of 3 min exercise at 80% HRR, and each interval was separated by 3 min recovery at 40% HRR. MICE was composed of 35 min exercise at 60% HRR. Both groups were designed to use same energy expenditure, and performed exercise 5 days/week for 4 weeks. Endothelial function was determined by assessing endothelial progenitor cells (EPCs) using flow cytometry and flow mediated dilation (FMD) using ultrasonography. Blood pressure (BP) and heart rate (HR) were measured at rest by using automatic blood pressure monitor. Repeated ANOVA was performed to analyze if the changes in dependent variables after training are different between HITT and MICE group. Statistical significance was at p< .05. Results There was a significant interaction in resting HR, but not in BP, FMD, and EPCs between groups after training. Systolic BP was significantly decreased in both HITT group (p = .012) and MICE group (p = .048) after training. However, diastolic BP and FMD was significantly decreased (p = .021) and increased (p = .049) in only HIIT group, respectively. EPCs were not significantly changed after training in both HIIT and MICE group. Conclusion The results of this study indicate that there is no big difference in HIIT and MICE for BP reduction, and HIIT and MICE are both effective for BP reduction in hypertensive patients. However, further researches are needed to illuminate differential effects of HIIT and MICE on BP response and endothelial function.