Abstract des Autors

Endurance athletes are susceptible to upper respiratory tract infection (URTI; e.g. colds, sore throats). In endurance athletes, the incidence of URTI is higher after competition and illness rates increase with yearly training volume. Both intense endurance and interval exercise have been shown to decrease the concentration of secretory IgA, the major effector of host resistance against microorganisms causing URTI. It has been previously suggested that the exercise-induced decrease in IgA levels may be related to the high incidence of URTI among athletes. The purpose of this study was to determine whether there is a temporal relationship between exercise-induced decreases in salivary IgA concentration and subsequent appearance of URTI in elite athletes. Two groups of athletes (squash and hockey) were followed over time, with saliva samples collected before and after exercise on a weekly (squash) or daily (hockey) basis. All episodes of illness were diagnosed by a medical practitioner. Salivary IgA concentration was measured by ELISA. Eleven of 12 episodes of URTI were preceeded, within two days, by a decrease in salivary IgA concentration after exercise (p<.05, chi square analysis). Absolute IgA concentration decreased 20-25% in athletes who developed URTI within two days, but decreased only slightly (<12%) or increased (10-20%) in athletes who were not developing URTI (p<.05). The data show a statistical temporal relationship between exercise-induced decreases in salivary IgA concentration and subsequent URTI, and suggest that changes in IgA during exercise may be one mechanism contributing to the high incidence of URTI in athletes. Verf.-Referat