Title : The therapeutic effect of ASP. linearis and HIIT exercise training in overweight/obese individuals - A randomized, controlled trial
Abstract:
The synergistic effects of Aspalathus (ASP.) linearis popularly known as Rooibos tea and HIIT on obesity-related outcomes in humans remain unexplored. Rooibos tea is a polyphenol-rich herbal tea and has demonstrated antioxidant and anti-inflammatory properties in preclinical studies. High-Intensity Interval Training (HIIT) is a time-efficient exercise modality known to improve metabolic health. While High-Intensity Interval Training (HIIT) has been widely recognized for its effectiveness in improving cardiovascular fitness, insulin sensitivity, and weight management, emerging research suggests that plant-based compounds such as polyphenols may offer complementary therapeutic benefits. This randomized controlled trial therefore investigated the therapeutic potential of rooibos supplementation, with or without HIIT, on body composition, cardiorespiratory fitness, metabolic function, and systemic inflammation in apparently healthy overweight and obese women. This study adopted a randomized controlled trial. Thirty-eight (38) physically inactive, apparently healthy, overweight/obese women were randomized into four groups: Rooibos only (R), Rooibos + Exercise (RE), Exercise only (E), and Control (CG). The intervention lasted 8 weeks. R and RE groups consumed six cups (12 g per 1200 ml of freshly boiled water) of tea daily, while exercise groups underwent HIIT sessions three times weekly. Pre- and post-intervention assessments included body composition, cardiorespiratory profile, metabolic functions and inflammatory markers, and dietary intake. Statistical analyses included ANOVA and ANCOVA for normally distributed data and the Kruskal-Wallis test for abnormally distributed data. Results were considered statistically significant at P≤0.05. The RE group showed significantly lower abdominal fat and sagittal abdominal diameter compared to the R group (p<0.05). CRP and hs-CRP levels significantly reduced in the E and RE groups. VO? peak and maximal fat oxidation were higher in exercise groups, though not statistically significant. Dietary intake remained consistent across groups, minimizing confounding effects. Aspalathus linearis supplementation combined with HIIT was associated with reduced central adiposity and systemic inflammation, suggesting a synergistic effect. These findings support integrating polyphenol-rich botanicals with structured HIIT exercise for improved obesity-related health outcomes. Future studies should explore longer durations and direct measures of cardiovascular risk factors to validate these effects.
