Application of intranasal oxytocin and affectionate touch reduce subsequent cortisol concentrations in romantic couples: Results from an ecological momentary assessment study

Social interactions and particularly affectionate touch are vital for mental and physical health. Research shows that affectionate touch is associated with release of oxytocin and has calming and stress reducing effects suggesting a regulatory effect of oxytocin on the hypothalamic pituitary adrenal (HPA) axis. Here, we aimed to systematically investigate the effects of repeated intranasal oxytocin administration on salivary cortisol. Furthermore, we focused on the moderating role of couples’ affectionate touch on biopsychological stress outcomes in everyday life. 80 heterosexual romantic couples (N=160 individuals) completed ecologically momentary assessments over five days. Six times per day participants answered smartphone-based questions regarding affectionate touch and momentary stress levels providing concomitant saliva samples for cortisol assessment. Half of the sample was randomly assigned to an instructed positive appraisal task. In a randomized double-blind design, both partners self-administered oxytocin or placebo on five days twice during the early evening. Multilevel analyses showed that oxytocin administration was associated with higher cortisol in the following morning and stronger decreases during the day. Subjectively reported momentary stress was associated with increase of affectionate touch in couples. Moreover, results indicate that participants, who received affectionate touch from their partner showed significantly lower cortisol levels after oxytocin administration. These results suggest that oxytocin administration paired with affectionate touch in romantic couples can influence HPA axis regulation as indicated via diurnal cortisol levels. Thereby, the data shed light on the neuroendocrine underpinnings of the health-promoting effects of intimate social relationships.