Search

Two important determinants of physiological stress responses have been identified, uncontrollability of the stressor and amount of effort involved in coping with the stressor. In the present experiment, we tried to identify the specific contributions of effort and uncontrollability to immune system responses to stress.In a 2 x 2 design, effort and uncontrollability were manipulated independently of each other. Subjects participated in one of four experimental conditions, and their endocrine, immune, and sympathetic nervous system responses to the task were assessed.Effort had a stimulating effect on enumerative immunological parameters (CD8+ and CD16+ cells) and on natural killer cell activity. The effect occurred immediately after the stressor and was transient. Regression models indicated that this effort effect may have been mediated by activation of the sympathetic nervous system. Uncontrollability influenced in vitro production of the cytokine interleukin-6, leading to decreased production 15 and 30 minutes after the stressor. Uncontrollability also led to an increased level of cortisol, but no evidence was found that the decrease in cytokine production was mediated by cortisol release.The results suggest that two major stressor characteristics, effort and uncontrollability, may have differential effects on the immune system. [ABSTRACT FROM AUTHOR]

Objective: Although stressor uncontrollability has been shown to suppress immune responses in animals and for human subjects, the results have been inconsistent. We reanalyzed results of our previous study regarding stress-related immune deviation in man, to establish whether perceived uncontrollability of an acute stressor acts as a co-determinant in the observed changes in immunological parameters.Method: Three types of cognitive reactions to an acute interpersonal stressor were assessed: "motivation," "uncontrollability," and "guiltiness." Stress-induced changes in the number of several types of immune cells in peripheral blood and proliferative responses of lymphocytes to antigens and mitogens were assessed.Results: In comparison with control subjects and with subjects perceiving high control over the experimental stress situation, the subject perceiving low control showed a stressor-induced decrease in the number of T helper cells. Reversely, subjects perceiving high control showed an increase in the number of B cells as opposed to the other two groups. The effects of perceived uncontrollability could not be accounted for by mood changes, but they were related to previously experienced life stress.Conclusions: Perceived uncontrollability of an acute stressor can have immuno-modulating effects over and above those of the stressor per se. [ABSTRACT FROM AUTHOR]

Objectives: To test the hypothesize that increased heart rate (HR) and decreased heart rate variability (HRV) are not only due to concurrent stressful events and worries but also to stressors and worries occurring in the preceding hours or stressors anticipated to occur in the next hour. Worry was expected to mediate at least part of the prolonged effects of stressors., Methods: Ambulatory HR and HRV of 73 teachers were recorded for 4 days, during which the participants reported occurrence and duration of worry episodes and stressful events on an hourly basis, using computerized diaries. Multilevel regression models were used, accounting for effects of several biobehavioral variables., Results: Stressful events were not associated with changes in HR or HRV. However, worry episodes had effects on concurrent HR and HRV (2.55 beats/minute; -5.76 milliseconds) and HR and HRV in the succeeding hour (3.05 beats/minute; -5.80 milliseconds) and 2 hours later (1.52 beats/minute; -3.14 milliseconds). These findings were independent of emotions, physical activity, posture, and other biobehavioral factors., Conclusion: Worry has effects on cardiac activity, and these effects were still visible after 2 hours. The latter finding suggests that a considerable part of prolonged activation may be induced by unconscious stress-related cognition.

Objective: To hypothesize that increased heart rate (HR) and decreased heart rate variability (HRV) occurs not only during stressful events but also during episodes in which stress is cognitively represented, but not necessarily present, i.e., during worry., Methods: Ambulatory HR and HRV of 73 female and male teachers were recorded for 4 days, during which they reported, on an hourly basis using computerized diaries, the number and characteristics of worry episodes and stressful events. Multilevel regression models were used, controlling for biobehavioral variables., Results: Compared with neutral periods, worry episodes and stressful events had independent effects on HR (2.00 beats/min and 2.75 beats/min, respectively) and HRV (-1.07 ms and -1.05, respectively). Neither psychological traits nor biobehavioral variables influenced these results. Effects were most pronounced for work-related worry on HR (9.16 beats/min) and HRV (-1.19 ms), and for worry about anticipated future stress on HR (4.79 beats/min)., Conclusions: Worry in daily life might have substantial cardiac effects in addition to the effects of stressful events, especially in the form of work-related and anticipatory stress, the latter being a type of stress that has been largely neglected in stress research.