Benefits of 10 weeks of high-intensity interval training and green tea supplementation on cardiovascular risk factors and VO(2max) in overweight women

BACKGROUND: Considered the increasing rate of cardiovascular diseases (CVDs) and a positive relationship between prevalence of CVDs and obesity, the goal of the present study was to investigate the effects of green tea supplement and high-intensity interval training (HIIT) on lipid panel, fibrinogen, and maximal oxygen consumption (VO(2max)) in overweight women. MATERIALS AND METHODS: In this randomized placebo-controlled clinical trial, 30 overweight women (age range, 20–30 years), were chosen purposefully and randomly divided into three equal groups (green tea, HIIT + green tea, and HIIT + placebo), and they trained HIIT workouts for 10 weeks (40-m maximal shuttle run) and used 500 mg/daily green tea or placebo tablets. Serum levels of low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG), and plasma level of fibrinogen were assessed before and after the intervention in fasting state. To test the hypothesis of the research, Paired t-test, Wilcoxon signed-rank test, analysis of covariance, and Tukey's post hoc tests were used at the significance level of P ≤ 0.05. RESULTS: After 10 weeks, TG, LDL, weight, fibrinogen, and body fat percentage decreased in all groups (P ≤ 0.05). Further, HDL (P = 0.012) and VO(2max) (P = 0.007) significantly increased in HIIT + green tea and HIIT + placebo groups; while in the green tea group, HDL (P = 0.06) and VO(2max) (P = 0.06) showed no significant difference for within group differences. Average between-group variations of all indicators were statistically significant, and they were more meaningfully pronounced in HIIT + green tea group than the other two groups (P ≤ 0.05). CONCLUSION: Based on the findings, the combination of HIIT and green tea consumption significantly leads to a reduction in weight, body fat percentage, fibrinogen, TG, and LDL while improves VO(2max) and HDL levels rather than green tea consumption or performing training alone, in overweight women. However, it seems that exercise training has a vital role in the improvement of mentioned variables according to percentage changes.