Preparing The Heart for Duty: Virtual Reality Biofeedback in an Arousing Action Game Improves in-action Voluntary Heart Rate Variability Control in Experienced Police

Adequate control over evolutionary engrained bodily stress reactions is essential to avoid23 disproportionate responses during highly arousing situations in police. This regulation can be trained24 via heart rate variability (HRV)-biofeedback, a widely used intervention aiming to improve stress25 regulation, but typically conducted under passive, low arousing conditions. We integrated closed26 loop HRV-biofeedback in a newly designed engaging Virtual Reality (VR) action game containing the27 behavioral elements typically compromised under stress. Specifically, we aimed to train in-action28 physiological self-control under high arousal to allow improved transfer to real-life. A pre-registered29 (https://osf.io/cdsbx) quasi-randomized controlled trial in 109 Dutch police trainers demonstrated30 highly significant increases in HRV (32% average), through the engaging and gamified closed loop31 biofeedback. This ability to voluntarily upregulate in-action HRV transferred to game sessions32 without biofeedback (near transfer). Critically, we could additionally demonstrate transfer to a33 professional shooting performance assessment outside VR (far transfer). These results suggest that34 real time-biofeedback in stressful and active action contexts can help train professionals such as35 police in real-life stress regulation