Salivary SIgA responses to acute moderate-vigorous exercise in monophasic oral contraceptive users

The purpose of this study was to examine the effect of oral contraceptive (OC) use on salivary secretory immunoglobulin A (SIgA) levels at rest and in response to an acute bout of moderate-vigorous exercise during two phases of the 4 week OC cycle corresponding to different phases of the synthetic menstrual cycle. Ten healthy active females completed a cycling at 70% V(・)O2peak for 45 min at two time points of an OC cycle: during the equivalent in time to the mid-follicular phase (day 8 ± 2) and the mid-luteal phase (day 20 ± 2). Timed unstimulated saliva samples were obtained before, immediately post exercise and 1 h post exercise and analyzed for salivary SIgA. Salivary SIgA secretion rate was 26 % (95% Confidence limits, CI, 6-46) lower at post-exercise compared with pre-exercise during the synthetic follicular phase (p = 0.019) but no differences were observed during the synthetic luteal trial. Saliva flow rate was 11% (95% CI, 8-30) lower at post-exercise compared with pre-exercise (main effect for time; p = 0.025). In conclusion, the pattern of salivary SIgA secretion rate response to moderate-vigorous exercise varies across the early and late phases of a monophasic OC cycle, with a transient reduction in salivary SIgA responses during the synthetic follicular phase. These findings indicate that monophasic OC use should be considered when assessing mucosal immune responses to acute exercise.