Autonomic nervous system reactions to secondary exposure to disaster-related imagery

Aim: This study investigated how disaster-related imagery affects emotional and autonomic nervous system (ANS) responses, using heart rate (HR) and heart rate variability (HRV), in individuals with indirect exposure to the 2011 Great East Japan Earthquake (GEJE). Methods: Thirty-six healthy adults who had experienced strong ground shaking during the GEJE, but not the tsunami directly, viewed four types of videos: natural scenery (neutral), earthquake scenes, tsunami footage, and promotional videos repeatedly broadcast after the disaster. Subjective emotional responses (State-Trait Anxiety Inventory, Positive and Negative Affect Schedule), HR, and HRV indices were measured before, during, and after each video. Results: Compared to the neutral video, disaster-related videos significantly decreased HR and HRV during viewing, indicating an orienting or freeze-type ANS response. Earthquake footage, likely to evoke autobiographic fear, predominantly suppressed parasympathetic indices, while tsunami footage, associated with vicarious fear, predominantly suppressed sympathetic activity. Immediately after viewing, sympathetic activation increased significantly, consistent with a rebound active defense pattern. Notably, promotional videos did not induce subjective distress but still altered HR and HRV indices, suggesting unconscious physiological reactivity. Conclusion: Disaster-related imagery evokes distinct ANS responses depending on the emotional content and the viewer's trauma history. Autobiographic and vicarious fear may differentially affect sympathetic and parasympathetic suppression, respectively. Furthermore, this cross-sectional evaluation demonstrates that even seemingly non-invasive media exposure years after a disaster can trigger autonomic changes. These findings underscore the urgent need for appropriate media broadcasting guidelines to protect public health following both seismic and climatic catastrophes.