震災映像が「時間差」で引き起こす自律神経の凍りつきと能動的防御反応のパターンを同定-「自覚なき身体的記憶」を心拍変動解析で可視化-

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2026-05-11 東北大学

東北大学の研究グループは、震災関連映像の視聴が自律神経に与える影響を心拍変動(HRV)解析によって調べ、映像視聴中と視聴後で異なる防御反応が生じることを明らかにした。東日本大震災で強い揺れを経験した成人を対象に、「地震」「津波」「震災直後の公共広告」映像を視聴させたところ、視聴中には心拍数と自律神経活動が低下する「凍りつき(フリーズ)」反応が生じ、視聴後には交感神経活動が急上昇する「能動的防御反応」が確認された。特に、直接的な災害映像ではない公共広告でも、本人の不快感の自覚とは無関係に自律神経反応が誘発され、「自覚なき身体的記憶」の存在が示唆された。これにより、災害映像への二次的曝露が無意識下で身体的ストレス反応を引き起こす仕組みの一端が明らかになった。本成果は、災害報道やSNS時代における二次的トラウマ対策、放送ガイドライン策定、公衆衛生上のメンタルケア戦略への応用が期待される。

震災映像が「時間差」で引き起こす自律神経の凍りつきと能動的防御反応のパターンを同定-「自覚なき身体的記憶」を心拍変動解析で可視化-
図1. 震災関連映像の視聴中と視聴後の自律神経の変化 映像視聴中には心拍数と自律神経活動が抑制される「凍りつき(フリーズ)」が生じ、視聴終了直後には一転して交感神経が亢進する「能動的防御反応」が起こる。

<関連情報>

災害関連映像の二次的曝露に対する自律神経系の反応 Autonomic nervous system reactions to secondary exposure to disaster-related imagery

Chiaki T. Ono ,Hironobu Kato,Yoshie Kikuchi,Zhiqian Yu,,Yumiko Hamaie,Mizuki Hino,Kazuho Tomimoto, Hiroshi Komatsu,+3 ,Hiroaki Tomita
Frontiers in Psychiatry  Published:11 May 2026
DOI:https://doi.org/10.3389/fpsyt.2026.1738606]

Abstract

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.

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