It is generally accepted that secretory immunoglobulin A (sIgA) is a major effector of local immunity in the oral cavity. The salivary sIgA level is known to be temporarily decreased after an acute single bout of intense exercise. On the other hand, the effect of continuous exercise training on salivary sIgA has been controversial. In the present study, we collected timed saliva samples from collegiate kendoists using the reliable saliva collection method that has already been reported. The collection was performed before, during and after a traditional high-intensity 10-day training camp during the coldest part of the winter. We investigated the effect of repetitious intense exercise training on resting sIgA levels in saliva.
The subjects were 19 males and 8 females (age: 19.9±0.5 years) who took part in the camp. We obtained saliva samples before the camp, on the first and the 10th days of the camp, and 4 and 10 days after the camp at 5 p. m. The concentration of sIgA was measured by ELISA, and the sIgA secretion rate was calculated.
The resting sIgA secretion rate decreased significantly during the camp. It remained at a lower level 4 and 10 days after the camp compared to the initial level, although it tended to recover gradually. Prolonged suppression of the resting sIgA secretion rate during a traditional winter kendo training camp might be induced by repetition of high-intensity training.