Positive Couple Interactions and Daily Cortisol: On the Stress-Protecting Role of Intimacy

Objective: To determine whether intimacy might be associated with reduced daily salivary cortisol levels in couples, thereby adding to the epidemiologic literature on reduced health burden in happy couples. Methods: A total of 51 dual-earner couples reported time spent on intimacy, stated their current affect quality, and provided saliva samples for cortisol estimation approximately every 3 hours in a 1-week time-sampling assessment. In addition, participants provided data on chronic problems of work organization. Results: Multilevel analyses revealed that intimacy was significantly associated with reduced daily salivary cortisol levels. There was an interaction effect of intimacy with chronic problems of work organization in terms of their relationship with cortisol levels, suggesting a buffering effect of intimacy on work-related elevated cortisol levels. Above this, the association between intimacy and cortisol was mediated by positive affect. Intimacy and affect together explained 7% of daily salivary cortisol variance. Conclusions: Our results are in line with previous studies on the effect of intimacy on cortisol stress responses in the laboratory as well as with epidemiologic data on health beneficial effects of happy marital relationships. HPA axis = hypothalamic-pituitary-adrenal axis; AUC = area under the individual response curve.