Just two 500 mg doses of the polyphenols increased the time to exhaustion by almost 10%, report scientists from the Faculty of Sports Science at the University of Burgundy -Franche-Comté, Nexira, and CEN Nutriment
In addition, the time to reach maximal perceived exertion (which can be considered as fatigue barrier) was delayed by almost 13%, according to findings published in Nutrients.
“[T]he present randomized, crossover, double-blind and controlled study demonstrated that the acute supplementation of polyphenols in healthy, physically active males allowed significant increases in endurance performance (hereby the capacity to maintain a strong effort) with greater energy expenditure as demonstrated by the lengthening of time to exhaustion and time to maximal perceived exertion,” wrote the authors.
“Also, the main cardiovascular and respiratory measured parameters showed no significant differences between conditions. A similar observation was obtained on muscle pain two days after exercise. These results indicate that performance improvements, as a result of acute polyphenol intake, have been obtained under safe conditions and without additional pain.”
Boosting nitric oxide synthesis
Damien Guillemet, Scientific Director at Nexira and co-author on the new paper, told NutraIngredients-USA that the study used the commercially ingredient ViNitrox, which is already formulated in some specific finished products designed for sport performance.
“Polyphenols are already known to have an impact on blood flow and benefits for sports performances,” said Guillemet. “But ViNitrox formulation has been especially designed through pre-clinical trials, to achieve the highest nitric oxide synthesis and then trigger a significant vasodilatation, thanks to a synergistic action of specific polyphenols class from grape and from apple.” (Guillemet added that the ingredient has also demonstrated antioxidant activity during in vivo trials.)
Guillemet noted that the study’s population size is bigger than usual (the trial included 48 physically active men), and that benefits were observed after acute administration. “Generally polyphenols based ingredients require a (sub)chronic administration to demonstrate a significant physiological impact,” he said.
The researchers recruited physically active men with an average age of 31 and randomly assigned them to receive 500 mg of polyphenols or placebo at two separate testing sessions.
The results showed that, compared to placebo, the time to exhaustion mean increased significantly by 9.7%, while the fatigue barrier was reached 12.8% later with polyphenols.
Commenting on the potential mechanism of action, the study authors noted that the polyphenols may be beneficially impacting endurance through an action on nitric oxide (NO), which is a potent vasodilator that improves blood flow.
“Additionally, polyphenols such as green tea or grape have been associated to improved endothelial function,” they wrote. “Based on in vivo and ex vivo preclinical unpublished observations with ViNitrox, we could speculate that performance benefits might be due to the modulation of NO-dependent vasodilation with NO synthesis increase and protection.”
Guillemet confirmed that Nexira is planning additional studies for the ingredient. “A hypothesis we proposed about the link between nitric oxide, vasodilation and sport performance improvements due to ViNitrox, is related to the oxygen debt created during the exercise,” he said. “We are thinking to continue our investigation to highlight how this modulation works. Moreover, exploring performance improvements for other kinds of exercise could be in our next investigations.”
2017, Volume 9, Issue 8, Page 917; doi:10.3390/nu9080917
“An Acute Dose of Specific Grape and Apple Polyphenols Improves Endurance Performance: A Randomized, Crossover, Double-Blind versus Placebo Controlled Study”
Authors: G. Deley et al.