Empathic stress is modulated by social closeness, observation modality and sex

Whether or not we directly suffer from stress, the question arises how much the stress inevitably unfolding around us has the potential to infiltrate and negatively affect us. We investigated whether such empathic stress, defined as a stress response that arises solely by observing a target undergo a stressful situation, would permeate to the core of the stress system, the hypothalamic-pituitary-adrenal (HPA) axis. Additionally, we investigated whether empathic stress responses may be modulated by the familiarity between observer and target (partners vs. strangers), the modality of observation (real-life vs. virtual) and observer sex (female vs. male). Participants were tested in dyads, paired with a loved one or a stranger of the opposite sex. While the target of the dyad (n = 151) was exposed to a psychosocial stressor, the observer (n = 211) watched through a one-way mirror or via live video transmission. Overall, 26% of the observers displayed physiologically significant cortisol increases. This empathic stress was more pronounced in intimate observer-target dyads and during the real-life representation of the stressor. Importantly, significant cortisol responses also emerged in strangers and the virtual observation modality. Empathic cortisol stress responses did not differ between men and women. When looking at the subjective-psychological component of stress, however, women exhibited empathic stress responses significantly more frequently than men. The occurrence of empathic stress down to the level of HPA axis activation, in some cases even in total strangers and when only virtually witnessing another’s distress, may have important implications for the development of stress-related diseases