Media-Dependent Effects in Heart Rate Variability Biofeedback: A Systematic Review of Extended Reality and...

Heart rate variability (HRV) is an indicator of autonomic nervous system function and cardiovascular health. Through biofeedback (BF), individuals can increase their HRV, which is ideal, by using audiovisual cues to monitor and adjust their breathing. HRV-BF training has demonstrated effectiveness in alleviating stress and anxiety, enhancing cardiac autonomic function, and supporting psychological treatments for conditions, such as depression and chronic pain. Despite their benefits, traditional HRV-BF approaches are limited by the need for frequent clinical visits, specialized equipment, and trained personnel, limiting accessibility and scalability. Extended reality (XR) technologies, including virtual reality, augmented reality, and mixed reality, offer a promising alternative by creating immersive, interactive environments that can deliver HRV-BF without traditional constraints. This review examines the available literature on reported differences in user experience (UX), HRV metrics, psychological outcomes, and BF performance, which are documented by research comparing HRV-BF using XR media to traditional screen-based methods. We searched PubMed, PsycINFO, Embase, Cochrane, Science Direct, ACM, and IEEE databases. Our search yielded 382 results. Four studies met our review criteria. Using HRV-BF research reporting guidelines, we extracted and summarized study objectives, design strategies, hypotheses, and related outcomes to evaluate the evidence for media-dependent effects. Findings indicate that both XR and screen-based implementations of HRV-BF positively affect HRV physiology. Furthermore, XR-based HRV-BF implementations showed more pronounced effects on outcomes for psychological and UX variables. These studies suggest that XR media can offer advantages in terms of user engagement and psychological benefits (e.g., stress relief, relaxation) over traditional screen-based modalities. Improvements in UX and psychological outcomes stem from the relaxing, immersive contexts created in XR, supporting user motivation and attentional control during XR-based HRV-BF training. However, design-based inquiries and longitudinal studies are needed to understand the role of design and the potential of the specific mechanisms contributing to these results.