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