Effect of High-Intensity Intermittent Exercise on Secretory IgA Response and Salivary Flow Rate

Abstract

2187 Athletes are susceptible to upper respiratory tract infection (URTI) during intense training and after major competition. Previous studies have shown that concentration and flow rate of secretary immunoglobulin A (s-IgA), the major of effector of host defence to URTI, decrease after intense exercise. These effects can be observed several hours after exercise, and the resulting transient immunosupression is postulated to be responsible for increased URTI episodes. PURPOSE: The purpose of this study was to examine the salivary IgA response during and after repeated bouts of brief, intermittent, maximal exercise. METHODS: Ten non-smoking, adult male rugby and hockey players (age = 24.4 years ± 3.41; body mass = 84.95 kg ± 9.42; stature = 186.3 cm ± 8.83) volunteered to participate in this study. The exercise intervention consisted of three consecutive, all-out 30-second Wingate (WAnT) leg cycle tests (0.098 kg. kgBW−1 kgBW) separated by 6 minutes of recovery. Unstimulated whole saliva was collected before, during and 1 and 24 hrs post exercise. Subjects also provided a saliva sample prior to the day of testing. Absolute salivary IgA concentrations were measured by ELISA and flow rates calculated. RESULTS: Salivary flow rates decreased significantly (P < 0.05) by 26%, 30% and 39% after each WAnT, before returning to resting levels 1 hr post-exercise. Salivary IgA secretion rates were significantly reduced (P < 0.05) after each WAnT (20%, 32% and 42% respectively), but did not return to base-line levels until 24 hrs post-exercise. No significant differences (P > 0.05) were observed for absolute IgA concentrations. CONCLUSIONS: These data suggest that salivary IgA flow rate decreases with bouts of maximal exercise, and that this is due, at least partially, to the reduction in salivary output. Further, there appears to be a specific effect of intense exercise on s-IgA concentration which is greater than that due to decreased saliva flow rate alone. Mucosal immunosupression was transient with s-IgA concentrations returning to base-line levels 24 hrs post-exercise. The results of this study suggest that reductions in s-IgA output after repeated bouts of maximal exercise may be one mechanism contributing to the higher incidence of URTI among athletes.