The viewing of a ‘Bloodcurdling’ horror movie increases platelet reactivity: A randomized cross-over study in healthy volunteers

J. J. K. van Diemen, A. van Dijk, C. Racca, T. Knol, T. N. Bonten, M. E. Numans, W. W. Fuijkschot, Y. M. Smulders, A. Thijs

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Background: Epidemiological studies have suggested an increased risk of cardiovascular events (CVE) during acute stressful and/or frightful moments. A possible explanation for this could be an effect of acute stress on hemostasis. A recent study demonstrated an increase in factor VIII after watching a horror movie. Primary hemostasis, however, is thought to play a more prominent role in the etiology of CVE. The objective of this study was therefore to assess the influence of viewing a ‘bloodcurdling’ horror movie on platelet reactivity in healthy volunteers. Methods: We performed a randomized cross-over study in healthy adults. Subjects were allocated to two movies in random sequence: a horror and a control movie. Blood was drawn at baseline and after 24 min of viewing time. The primary endpoint was the change in Platelet Function Analyzer® Closure Time (Δ PFA-CT) after watching the movie. Results: In total, 20 participants, aged 18–30 years, completed the study protocol. The delta PFA-CT was statistically significantly shorter with a mean in the delta difference of −9.7 s (SEM 4.0, 95% C.I. −18.0 to −1.3) during the horror movie versus the control movie. The Light Transmission Aggregometry endpoints were in line with the PFA-CT, albeit only the highest level of Arachidonic Acid agonist demonstrated a statistically significant mean difference in the delta of aggregation of 13.15% (SEM 7.0, 95% C.I. 1.6–27.9). Conclusion: A ‘blood curdling’ horror movie increases platelet reactivity. These data are supportive of a role of platelet reactivity in acute stress induced cardiovascular event risk.
Original languageEnglish
Pages (from-to)27-32
JournalThrombosis research
Publication statusPublished - 2019


  • Fear/physiology
  • Fear/psychology
  • Platelet activation
  • Platelet function test

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