The short-term effects of effort-reward imbalance : Daily and within-day psychological and physiological measurements

Abstract

In the present thesis, the short-term effects of Effort-Reward Imbalance (ERI) are studied by measuring indices of vagal control, hypothalamo-pituitary-adrenocortical (HPAC) activity and affect. The studies provide an illustration of recent developments in the field. Primarily, Ecological Momentary Assessment (EMA) provides information on psychological measurements throughout the day, and reveals information not accessible using traditional single occasion assessments of perceived work related stress. In this thesis both traditional and EMA measurements were performed. Is spite of the extensive nature of the studies, only limited and indirect empirical support was found for the hypothesised relation between work stress and physiology measured throughout the day. Only need for control is positively related to vagal withdrawal, and negative mood is related to an increase in cortisol secretion throughout the day. These results are of interest to psychobiology in general, but are not of direct importance to the work - stress relation. Based on face validity, it is argued that need for control and negative mood are related to the type A construct and trait negative affect, respectively, constructs that hardly reflect work stress alone. The present thesis uses sophisticated state-of-the art assessment methods and analysis techniques to determine the short-term physiological effects of ERI. Based on the evidence from the present thesis, it may be concluded that the widely held assumption - that work stress is associated with physiological changes in an individual -, does not hold, at least for the normal working population studied here. This questions the pursuit of short-term physiological effects of work stress in a normal working population. Probably, such attempts will remain fruitless till a different approach is used. More attempts should be made to assess objective environmental demands, or to use physiological changes to identify individuals "at risk", instead of trait-like individual perceptions.