The Effects of Polyphenol Supplementation on BDNF, Cytokines and Cognition in Trained Male Cyclists following Acute Ozone Exposure during High-Intensity Cycling

Abstract

The neurotoxic effects of ozone exposure are related to neuroinflammation and increases in reactive oxygen species (ROS). This study aimed to assess inflammation, Brain-Derived Neurotrophic Factor (BDNF), and cognition in healthy male cyclists following polyphenol supplementation and exercise in an ozone-polluted environment. Ten male cyclists initially completed a maximal incremental test and maximal effort 4 km time trial in ambient air. Cyclists then completed two trials in an ozone-polluted environment (0.25 ppm) following 7 days of supplementation with either polyphenol (POLY) or placebo (PL). Experimental trials consisted of a three-stage submaximal test followed by a 4 km time trial. Blood samples were drawn pre- and post-exercise, and analyzed for BDNF, interleukin 6 (IL-6), interleukin 10 (IL-10) and tumor necrosis factor (TNF-α). The Stroop test and serial subtraction task were performed before ozone exposure and again after the 4 km TT. Serum BDNF increased post-exercise (p < 0.0001), and positive differences were observed post-exercise in the ozone POLY group relative to PL (p = 0.013). Plasma IL-6 increased post-exercise (p = 0.0015), and TNF-α increased post-ozone exposure (p = 0.0018). There were no differences in Stroop or serial subtraction tasks pre- or post-exercise. Exercise increases BDNF in ozone.