Secretory immunoglobulin A and cardiovascular activity during mental arithmetic: effects of task difficulty and task order

Secretory immunoglobulin A (sIgA) in saliva and cardiovascular activity wer e measured at rest and during mental arithmetic. Task difficulty was manipu lated by presenting easy, hard, and impossible versions of the mental arith metic task in counterbalanced order, while task novelty was operationalised as order of presentation (i.e. first, second, third). Mental arithmetic el icited significant increases in sIgA concentration and sIgA secretion rate, as well as significant cardiovascular effects. Performance decreased and r ated difficulty increased with increasing task difficulty. However, sIgA an d cardiovascular activity, with the exception of diastolic blood pressure, were insensitive to variations in task difficulty. In contrast, sIgA concen tration and a broad range of cardiovascular variables were influenced by ta sk novelty, with more pronounced activity characterising the task version p resented first, irrespective of its level of difficulty. Task novelty would seem to be a more important determinant of sIgA and cardiovascular activit y than task difficulty. (C) 2000 Elsevier Science B.V. All rights reserved.