Purpose: Excessive reactive oxygen species (ROS) induced by prolonged high-intensity exercise can cause structural and functional damage. Antioxidant polyphenol supplementation, which reduces ROS levels, may improve high-intensity exercise performance. We evaluated the effect of lychee fruit extract, which contains high levels of low-molecular-weight oligomerized polyphenols, on high-intensity exercise performance.
Methods: Ten male athletes were included in an open-label trial that consisted of control and intervention phases, with a 7-day washout period between phases. The participants were administered oligomerized lychee fruit extract for seven days, whereas no intervention was given in the control phase. High-intensity intermittent exercise and the Wingate test were performed. The power output, blood lactate levels, reactive oxygen metabolite levels, biological antioxidant potential, heart rate, and rate of perceived exertion were measured.
Results: The average power output was significantly higher in the intervention phase than in the control phase (p < 0.01), while the change in blood lactate levels was significantly lower in the intervention phase than in the control phase (p < 0.05). The average heart rate was significantly higher in the intervention phase than in the control phase (p < 0.05), without changing the rate of perceived exertion. Although there was no difference in reactive oxygen metabolite levels between the phase, the change in biological antioxidant potential was larger in the intervention phase than in the control phase (p = 0.06). The Wingate test showed no significant differences between the phase.
Conclusion: Short-term loading with oligomerized lychee fruit extract may increase performance during high-intensity intermittent exercise by improving metabolism.
Keywords: antioxidant capacity; fruit polyphenols; high-intensity intermittent exercise; oligomerized lychee fruit extract; power output; reactive oxygen metabolites.