Salivary immunoglobulin A and salivary cortisol responses to training and competition in athletes from team sports and combat sports

Abstract

There has been a substantial increase in research dedicated to determining the relationship between exercise, immune function and steroids hormones, particularly, the called stress hormone. The adaptation to physical or psychological stress usually involves the activation of the hypothalamic cortico-tropin-releasing hormone, anterior pituitary adrenocorticotropic hormone, and adrenal glucocorticoids (cortisol and corticosterone) in anticipation of or during stressful situations understanding as a homeostatic response of the body. Among the hormones reacting to exercise and stress, cortisol is probably the more affected. Due to altered circulating levels with different forms of exercise, cortisol has been used to determine the physiological stress imposed during single and repeated exercise sessions. It has been proposed that metabolic stress stimulates the HPA, leading to an increased secretion of hormones such adrenocroticotropic hormone (ACTH) and cortisol, consistent with the increased susceptibility to contracting upper respiratory tract infection (URTI). Various authors have utilized the salivary concentrations of immunoglobulin A (SIgA) to investigate the relationship between exercise training load, immune function and URTI incidence. Levels of salivary immunoglobulin A (SIgA) are lower in athletes engaged in heavy training. It has been suggested that changes in concentration of SIgA also may act as a marker of excessive training. In addition, psychological stress is also thought to influence mucosal immune function. Sustained periods of psychological stress have been associated with reduction in SIgA concentrations. Some studies utilizing SIgA concentration to investigate the relationship between mucosal immune function changes with training and incidence of URTI. Salivary immunoglobulin A is the predominant immunoglobulin in mucosal fluids, serving to inhibit the attachment and replication of pathogens and neutralize viruses and toxins. Salivary immunoglobulin A concentration and secretion rate has been show to correlate more closely with URTI than changes in serum antibodies or other immune parameters. Although the implications of an observed impact on SIgA and salivary cortisol levels following heavy exercise are of great interest to sport scientists, relatively few data have been obtained in a true environment setting among team sports and combat sports, especially employed longitudinal studies. The aims of the present study are 1) to assess possible changes in SIgA and salivary cortisol after training and competitive sessions in team sports and combat sports athletes, 2) examine the impact of distinct training phases on mucosal immune parameters, salivary cortisol levels, sources and symptoms of stress and perceived symptoms of URTI, 3) verify the relationship between training load, SIgA measures, salivary cortisol levels and incidence of URTI, 4) determine which SIgA expressions could better predicts URTI. (AU)