The relationship between brain-derived neurotrophic factor, irisin and cognitive skills of endurance athletes

Objective: The objective of this study was to assess the cognitive performance of endurance athletes and its relation with circulating brain-derived neurotrophic factor (BDNF) and irisin levels.Methods: 26 endurance athletes (14 elite orienteers (mean SD: age=26.334.08, body weight=70.33 +/- 4.64, body height=177.7 +/- 6.1), 12 pentathletes (mean +/- SD: age=29.42 +/- 5.32, body weight=74.77 +/- 6.59, body height=180.8 +/- 3.8)) and ten sedentary (mean +/- SD: age=27.30 +/- 2.06, body weight=76.65 +/- 12.50, body height=176.9 +/- 5.2) men at almost same ages and educational levels participated in this study. Cognitive functions were analyzed with mini-mental-state examination (MMSE) and Isaacs' Set Test of Verbal Fluency (IST) tests. Insulin-like growth factor-1 (IGF-1), BDNF and irisin levels were measured in the blood samples.Results: The MSSE and IST scores of the endurance athletes were higher than that of the sedentary control group (P<0.05). Serum IGF-1 levels were higher in the pentathletes (111.18 +/- 22.26 ng mL(-1)) than the orienteers (85.89 +/- 19.32 ng mL(-1)) (P<0.05). Plasma BDNF (2.78 +/- 0.81, 4.28 +/- 1.03, and 3.93 +/- 0.77 ng mL(-1) in the sedentary, orienteers and pentathletes, respectively) and irisin (3.25 +/- 0.70, 6.16 +/- 0.99, and 6.58 +/- 1.09 mu g mL(-1) in the sedentary, orienteers and pentathletes, respectively) concentrations of the endurance trained athletes were higher than that of the sedentary control group (P<0.05). Positive correlation between the cognitive function test results and BDNF and irisin concentrations were observed (P<0.05). There was also a positive correlation between the circulating irisin and BDNF concentrations (P<0.05).Conclusion: These results suggested that irisin and BDNF levels positively correlated with cognition in the endurance trained athletes.