title: Effect of competition on salivary cortisol, immunoglobulin A, and upper respiratory tract infections in elite young soccer players.
abstract: The present study examined the effect of a 20-day period of competition on salivary cortisol, mucosal immunity, and upper respiratory tract infections (URTI) in young male soccer players (n = 14). The players were monitored during the main under-19 Brazilian soccer championship, in which 7 matches were played in 20 days. Saliva samples were collected in the morning of each match and analyzed for cortisol and immunoglobulin A (IgA). Signs and symptoms of URTI were assessed across the study and a rating of perceived exertion (RPE) was obtained for each match. Compared with match 1, a significant increase in player RPE was observed in matches 4-7 (p < 0.05). Significant (p < 0.05) increases in the reporting of URTI occurred between matches 2 and 3, and 6 and 7, and this was accompanied by significant decreases in salivary IgA levels. Significant (p < 0.05) correlations were also seen between the individual reports of URTI and the decrease in IgA levels in match 2 (r = -0.60) and match 6 (r = -0.65). These results suggest that decrements in mucosal immunity, as measured by salivary IgA concentrations, may lead to a greater incidence of URTI in elite young soccer players. It may be speculated that the physiological and psychological stressors imposed by training and competition in a short timeframe are major contributing factors to these responses. Thus, the monitoring of salivary IgA could provide a useful and noninvasive approach for predicting URTI occurrences in young athletes during short-term competitions, especially if frequent sampling and rapid measurements are made.
authors.affiliation: Physical Education and Sports Institute, Ceará Federal University, Fortaleza, Brazil.
authors.forename: Arnaldo L
authors.initials: AL
authors.lastname: Mortatti
authors.forename: Alexandre
authors.initials: A
authors.lastname: Moreira
authors.forename: Marcelo S
authors.initials: MS
authors.lastname: Aoki
authors.forename: Blair T
authors.initials: BT
authors.lastname: Crewther
authors.forename: Carlo
authors.initials: C
authors.lastname: Castagna
authors.forename: Ademir F S
authors.initials: AF
authors.lastname: de Arruda
authors.forename: José M
authors.initials: JM
authors.lastname: Filho
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D003163:Competitive Behavior / Q000502:physiology*; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D018928:Immunity, Mucosal; D007070:Immunoglobulin A / Q000276:immunology / Q000378:metabolism*; D008297:Male; D005082:Physical Exertion; D012141:Respiratory Tract Infections / Q000276:immunology*; D012463:Saliva / Q000276:immunology / Q000378:metabolism*; D012916:Soccer / Q000502:physiology*
chemical_list: D007070:Immunoglobulin A; D006854:Hydrocortisone