Momentary emotions and salivary cortisol: A systematic review and meta-analysis of ecological momentary assessment studies.

An integrated view of the stress response requires consideration of both the emotional and hormonal sequelae of stress, which are regulated by the hypothalamic-pituitary-adrenal (HPA) axis. Understanding the extent of the association between emotions and cortisol at the momentary level can shed light on the biopsychological pathways linking stress to health. Research in this area has adopted heterogeneous approaches and produced mixed findings; thus, it is critical to conduct a systematic review and meta-analysis. Systematic searches in major databases identified 22 studies (negative emotions [k = 19; 38,418 momentary observations]; positive emotions [k = 15; 31,721 momentary observations]). Meta-analysis found a significant positive association between momentary negative emotions and cortisol (r = .06, p < .001) and a significant negative association between momentary positive emotions and cortisol (r = -.05, p = .003). No methodological differences moderated these associations. Our findings suggest that emotional states correlate with cortisol levels at the momentary level. We discuss the health implications of our findings and provide recommendations for advancing this area of research.