Experimentally Induced Post-Event Rumination Alters Biological Stress Response Patterns to Repeated Stress

Objective: Rumination – the repetitive negative thinking about stressful events – impairs biological stress system activity. However, its impact on the habituation of stress responses, particularly of the sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis, remains understudied. This study examined how post-event rumination affects the habituation of biological responses to repeated stress. Methods: In this randomized experimental study, 47 participants were assigned to a rumination or control condition and exposed to two consecutive stress tasks. After the first stress exposure, the rumination group engaged in guided post-event rumination, while the control group reflected on a neutral everyday topic. Biological markers of HPA axis and SNS activity (cortisol and salivary alpha-amylase, sAA), as well as psychological variables (positive and negative affect, state rumination), were assessed before and after each stressor. Results: Compared to the control group, participants in the rumination condition showed reduced habituation of HPA axis activity ( t (45)=−2.01, P =.025) and increased SNS activation over time, as indicated by rising sAA levels ( t (45)=−2.03, P =.024). No significant group differences were observed in self-reported affect or state rumination. Conclusions: Post-event rumination impairs biological habituation to repeated stress. These findings suggest that rumination disrupts physiological stress adaptation, which may contribute to prolonged stress responses and increased risk for stress-related health problems. Interventions targeting rumination may support more adaptive stress regulation and promote better health outcomes.