The incidence of SLC6A4 gene 5HTTLPR polymorphism alleles was evaluated in 223 male athletes engaged in endurance sports, the results were compared with those in 177 male nonathletes. Association between 5-HTTLPR genotypes and the effect of exhaustive treadmill running on simple and complex visual reactions and critical flicker frequency threshold was studied. We found that the incidence of LL genotype was significantly higher in athletes in comparison to nonathletes; after exercise, the velocity of visual reactions and critical flicker frequency increased; exercise did not change the velocity of complex visual reaction in LL-carriers, and increased it in SS-carriers. We conclude that exhausting treadmill running leads to facilitation sensory information processing in athletes and that SS-carriers are more susceptible to the effect of exhaustive treadmill running than LL-carriers.