Effects of a Multimodal Immersive Virtual Reality Intervention on Heart Rate Variability in Adults with Post-COVID-19 Syndrome

Background: Post-COVID-19 syndrome (PCC) is characterized by autonomic nervous system (ANS) dysregulation. Reduced heart rate variability (HRV) serves as a biomarker for ANS function. Few studies have assessed HRV modulations over treatment in PCC patients. This study evaluates the effects of a multimodal immersive virtual reality intervention—integrating cognitive training, physical exercise, and mindfulness practices—on HRV parameters. Methods: Eighteen PCC adults were assigned to reduced (16 sessions) and extended (24 sessions) training. HRV was assessed using an electrocardiogram weight scale at baseline, in the mid-term, and at the end of the intervention. Time-domain and frequency-domain HRV measures were extracted. Results: No significant group-by-time interactions were found. However, certain time-domain HRV parameters showed significant changes over time. Unexpectedly, HRV decreased from baseline to mid-intervention in both groups, with recovery by the end of the intervention. No significant changes were observed in frequency-domain measures. Conclusions: The temporary reduction in HRV suggested that the initial cognitive and physical demands may have temporarily induced physiological stress. The subsequent restoration of HRV suggested adaptation and increased resilience. The absence of enhanced HRV with extended training suggests that session intensity may be more influential than the number of sessions in modulating HRV among PCC patients.