Acute Effects Of Different Exercise Intensity And Duration On Salivary Antimicrobial Peptide Secretion

Human β-defensin-2 (HBD-2) which is secreted by epithelial cells in the oral cavity and respiratory tract plays an important role in oral immune function through exerting antimicrobial activity against pathogens such as bacteria and viruses. Salivary HBD-2 secretion increases with a single bout of aerobic exercise. However, it is unclear whether acute effects of different exercise intensities and durations on salivary HBD-2 secretion. PURPOSE: To clarify acute effects of different exercise intensities and durations on salivary HBD-2 secretion. METHODS: Ten healthy young men randomly performed [Intensity study] cycling exercise for 30 minutes at 35%, 55%, and 75% maximal oxygen uptake (VO2max) and [Duration study] cycling exercise for 30, 60, and 90 minutes at 55% VO2max. Saliva collections were taken before, immediately after, and 60 minutes after each exercise. The salivary HBD-2 concentrations were measured by enzyme-linked immunoassay. The amount of salivary HBD-2 secretion rate was calculated by multiplying the salivary HBD-2 concentrations by saliva flow rate. RESULTS: In the Intensity study, no significant differences in the percentage change in salivary HBD-2 secretion rate from baseline (before exercise) were observed immediately after exercise at three exercise intensities. However, the percent change in salivary HBD-2 secretion rate was significantly higher 60 minutes after exercise compared to before exercise at 35% and 75% VO2max exercise intensity (P < 0.01 and P < 0.05, respectively), but did not change at 55%VO2max exercise intensity. Meanwhile, in the Duration study, no significant differences in the percentage change in salivary HBD-2 secretion rate from baseline were observed among three different exercise duration trials. CONCLUSION: These results suggest that salivary HBD-2 secretion may differently respond to exercise intensity and duration. Supported by Grants-in-Aid for Scientific Research (#22H03487, M. Iemitsu)