Acute Effects Of Different Exercise Patterns On Salivary IgA And Antimicrobial Peptide Secretion

Salivary immunoglobulin A (IgA) and human β-defensin-2 (HBD-2) are key players of immunity in the oral cavity and prevent upper respiratory tract infections by neutralizing activity and antibacterial activity. Several previous studies showed that continuous aerobic exercise caused secretion levels of lower IgA and higher HBD-2 in saliva. However, the acute secretory responses of salivary IgA and HBD-2 to different exercise patterns remain unclear. PURPOSE: The purpose of this study was to investigate acute effects of different exercise patterns with same total volume exercise on salivary HBD-2 and IgA secretion. METHODS: Twelve healthy young males with no exercise habits participated in the study. Subjects randomly performed two exercise patterns with same total volume exercise: moderate intensity continuous exercise (MICE) for 20 min cycling exercise load equivalent to 70% VO2max, and high-intensity interval exercise (HIIE) for 20 min cycling exercise, with 5 sets of 2 min at 50% VO2max and 2 min at 90% VO2max. Saliva samples were collected before (baseline), immediately after (post), 30 min after each exercise (post-30 min) condition. The salivary IgA and HBD-2 concentrations were measured by enzyme-linked immunoassay. The amount of salivary IgA and HBD-2 secretion rate was calculated by multiplying the salivary IgA and HBD-2 concentrations by saliva flow rate. RESULTS: In the HIIE, the percentage change in salivary IgA secretion rate did not decrease from baseline to after exercise. In contrast, in the MICE, the percentage change in salivary IgA secretion rate was lower immediately after exercise. Furthermore, the percentage change in salivary IgA secretion rate immediately after exercise decreased in the MICE as compared to the HIIE. However, the percentage change in salivary HBD-2 secretion rate did not change from baseline to immediately after exercise in the MICE and the HIIE. Moreover, the salivary flow rate from baseline to after exercise did not change due to differences in exercise patterns. CONCLUSIONS: These results suggest that salivary IgA secretory response to acute exercise may differ between exercise patterns, despite the same total volume exercise. Supported by: Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan (KAKENHI: 23 K24744 to M. Iemitsu)