Introduction: Intense exercise is known to cause temporary impairments in immune function. Few studies, however, have investigated the effects of intense competitive sports on immunoendocrine variables in athletes. Therefore, the purpose of this study was to explore the effect of sport competition on responses of salivary immunoglobolin A (sIgA), cortisol and their relationships in adolescent karateka.

Materials & methods: Ten boys karateka with average ages of 13.1±.9 yr, weight: 58±9.7 kg, and body mass index: 20.3±2.4 kg/m2, that acceded to final competition of Ilam province were selected as subjects of this study. Unstimulated saliva samples were collected to measure sIgA and cortisol levels with ELISA method before, immediately and 2 hours after competition. In order to analyze the data, Shapiro-Wilk, analysis of variance (ANOVA) with repeated measurements, Bonferroni and Pearson’s correlation tests at the significant level of p<0.05 were utilized. 

Findings: The sIgA level of adolescent karateka significantly decreased immediately in comparison with before competition (p=0.002), and increased significantly 2 hours after in comparison with immediately after competition (p=0.04). Also, the cortisol level of adolscent karateka increased significantly immediately (p=0.004), and 2 hours after in comparison with before the competition (p=0.038). In addition, there were no significant relationships between changes in sIgA and cortisol immediately (r=-0.47, p=0.16) and 2 hours (r=-0.36, p=0.22) after competition.

Discusion & Conclusions: This results indicated that, official karate competition maybe with stimulating the Hypothalamic-Pituitary-Adrenal (HPA) axis, causes increase in cortisol level and decrease of sIgA. It is concluded that, participant in karate competition suppressed mucousal immune system and enhanced possible risk of upper respiratory tract infection. Therefore, it could be necessary to take protective actions to minimize contact with pathogens or even reduce the training load for athletes.