陸上長距離選手における暑熱環境での唾液中免疫グロブリンAの分泌低下とその要因の検討

Abstract

Depressed immune function during intensive training is associated with higher incidence of illness in athletes. Previous reports have suggested that resting salivary secretory immunoglobulin A (sIgA) levels are correlated with the incidence of upper respiratory tract infection symptoms. This study aimed to evaluate changes in sIgA of male long-distance runners during the summer. Fifteen male long-distance runners aged 19±0 years were examined during the summer (June to July) and fall (October to November). Wet-bulb globe temperature was measured during training. Heart rate and rate of perceived exertion were recorded to monitor exercise intensity. Saliva samples were collected before and after training, and saliva flow rate and sIgA concentration were determined by enzyme-linked immunosorbent assay and expressed as secretion rate. Mood states, including total mood disturbance (TMD), were assessed using the Profile of Mood States. Energy and nutrient intake was evaluated using a food frequency questionnaire. After long-distance running during the summer, sIgA secretion rate was decreased and TMD was increased. Resting sIgA secretion rate was significantly lower during the summer than during the fall. There were no significant differences in energy or nutrient intake between summer and fall except for iron intake. These findings suggest that intensive exercise during the summer increases psychological stress and decreases sIgA secretion rate in long-distance runners.