The Defined Intensity Stressor Simulation (DISS): The effects of increasing intensity on S-IgA reactivity and perceptions of workload, stress and arousal

Background: A variety of laboratory-based acute stressors have reliably induced increases in S-IgA secretion. Previous work assessing acute multi-tasking stress suggests that S-IgA reactivity is inversely related to the perceived demands of the stressor. The DISS comprises eight stressor modules, and allows for the manipulation of stress either through increasing the number of modules, or increasing the difficulty of the modules. The current study assessed the effects of increasing the difficulty of four stressor modules (visual and auditory monitoring, a maths task and an attention/reaction time task) upon S-IgA reactivity and perceptions of the stressor. Methods - Participants (N = 14) attended three sessions on consecutive days. At each session they provided a timed saliva sample immediately before and after five minutes on the stressor battery at either low, medium or high stress intensity. Immediately following each session participants recorded, using questionnaires, their perceptions of the stressor with regard to workload and levels of stress and arousal. Results - Different patterns of S-IgA reactivity were observed at varying levels of stress intensity. Low intensity stress resulted in a slight increase in S-IgA secretion, medium intensity stress elicited a significant increase, while downregulation of S-IgA occurred following high stress intensity. Increased stressor intensity was related to significant increases in several facets of perceived workload and increases in perceptions of stress, but not arousal. Conclusions - Perceptions of workload and stress increased in accordance with increases in the difficulty of four DISS stressor modules. However, increasing intensity had differential effects upon S-IgA reactivity. Down-regulation of S-IgA following high intensity stress supports the previous finding regarding reduced reactivity in individuals who report tasks to be more demanding.