Stress is contagious: Observing others in distress triggers a cardiovascular stress response shaped by affective empathy

Recent studies show that our body reacts to stress not only when it is directed toward the self, but also when we simply observe someone else facing a stressor. Research on vicarious stress has primarily examined the effects on hypothalamic-pituitary-adrenal (HPA) axis, while its impact on the cardiovascular system remains largely unknown. Moreover, existing studies have largely relied on low ecological paradigms, limiting the generalizability of findings to real-life scenarios. Here we present the results of a study designed to overcome these limits. We employed a modified version of the Trier Social Stress Test (TSST) to have a more ecological dyadic setting, in which one participant was the target of the stressor, while the other was the observer. One hundred healthy dyads participated in the study. Results showed that real-life observation of stress induction in others prompts consistent changes in heart rate and heart rate variability. Furthermore, individual differences in empathy are predictive of the magnitude of this vicarious activation, with larger cardiovascular stress responses among individuals with high sensitivity to resonate with others’ emotional states. Interestingly, this psychophysiological reactivity was not mirrored in a change in anxiety and negative emotions elicited by watching the target’s stress, and did not appear to vary as a function of the type of relationship linking the observer to the target.Results of this study add to the emerging field of vicarious stress research, emphasizing the importance of understanding the role of the cardiovascular system in this phenomenon, which appears to occur with a differential strength according to individual differences in empathy. This is relevant in light of the potential implications of systematic exposure to others’ stress can have for individual well-being and cardiovascular health.