Secretory immunoglobulin A reactions to prolonged mental arithmetic stress: inter-session and intra-session reliability.

Although previous evidence suggests that mucosal immunity may be influenced by mental stress, the importance of the duration of stress exposure on secretory immunoglobulin A (sIgA) has yet to be fully elucidated. Salivary sIgA and cardiovascular activity were measured at rest, following 14 and 28 min of mental arithmetic, and after recovery in 24 men and women on two sessions 2-4 days apart. Mental arithmetic was, on both sessions and after both the early and late phases of the task, associated with increases in sIgA concentration and sIgA secretion rate compared to rest and recovery. Task levels of sIgA concentration and sIgA secretion rate showed moderate to high intra- and inter-session test-retest reliability, while test-retest reliability was lower for change scores. Blood pressure and pulse rate were also elevated by the mental stress task, although correlational analyses revealed that stress-induced changes in sIgA were not related to cardiovascular reactions.