A forward-facilitating influence of cortisol on catecholamines assessed during the work of garbage collectors

Objectives In this study, the hypothesis was tested of whether part of the hypothalamic-pituitary-adrenal system can have a facilitating influence on mean adrenomedullary reactivity during a workday. Methods Data of a field study on 115 male garbage collectors were used for this purpose. Catecholamines and cortisol were assessed by urinary sampling during a workday and during a day off. The within-subjects baseline levels of the catecholamines, personal factors, physical work load, and work characteristics were controlled for in the analyses. Results The results showed that there is reason to assume a "forward-facilitating influence" between the aforementioned systems. The morning cortisol excretion rate explained a reasonable amount of the mean catecholamine excretion rates during a workday. The morning cortisol level explained more variance in the adrenaline than in the noradrenaline values, and for both catecholamines the influence of cortisol was more pronounced than the influence of psychosocial stress factors like autonomy and job demands. Conclusions The morning level of cortisol proved to be a more powerful predictor of the reactivity of adrenaline than that of noradrenaline during work. The association between the pituitary adrenocortical system and the adrenomedullary system could therefore be a "forward-facilitating influence". It is recommended that future research should focus on cortisol as the predictor of neuroendocrine reactivity and on determining whether this predictive power is expandable to work-induced health complaints.