Pure purr virtual reality technology: measuring heart rate variability and anxiety levels in healthy volunteers affected by moderate stress

Abstract

Introduction: Traditional approaches to stress management are difficult to learn and to implicate in daily life. Emerging technologies like virtual reality (VR) have become a target of extensive study for recreational and medical purposes. The autonomic nervous system (ANS) plays a crucial role in stress response, post-stress relaxation, and recovery. This study aimed to assess the effect of modified VR intervention on short-term heart rate variability (HRV) and perceived anxiety levels in healthy volunteers affected by moderate stress. The stressors included mental arithmetic tasks.

Material and methods: The study involved healthy adults, of both sexes, aged 20 to 60 years, without history of cardiovascular diseases, essential abnormalities on ECG, and with normal or moderate level of situational anxiety. The VR gadgets used in the study were commercially available Bobo-VR X1 headsets, one with modification for medical applications (Pure Purr technology) and one with none (sham technology). The investigational (Pure Purr) headset with an audio-visual sequence was modified by adding a binaural effect and was synchronised with the tract of respiratory movements and the frequency of heart rate. To track changes in the ANS, participants underwent both electrocardiography (ECG) and measurement of HRV.

Results: The findings showed a significant increase in parasympathetic activity after 5-minute exposure to the investigational device compared to stress, as shown by high-frequency HRV (499.8 ms² and 340.5 ms², p < 0.001). RMSSD for a modified headset was higher (p = 0.02) compared to a sham headset with no modifications (RMSSD difference of 12.3% (2.6% to 23.1%)). The LF/HF ratio, however, was lower (difference of 14.5% (2.6% to 23.1%), p = 0.04).

Conclusions: These findings suggest that a medical device with pre-installed Pure Purr software had a significant effect on the recovery of the ANS in healthy volunteers affected by moderate stress.

Keywords: heart rate variability; parasympathetic neurostimulation; stress; virtual reality.

Figure 1

Virtual environment scenes. A – investigational device, B – sham virtual reality scene

Figure 2

Study protocol. Visit 1 goals: select and randomise participants; obtain informed consent; STAI assessment; 5-min ECG at rest (stage 1); 5 min of moderate stress by mental arithmetic with second ECG (stage 2); 5-min VR session 1 (active or sham) with third ECG (stage 3); 5-min ECG after VR intervention, STAI assessment (stage 4). At least 1 day and night after visit 1 (a night’s sleep was mandatory). Visit 2 goals: check exclusion criteria; 5-min ECG at rest (stage 1); 5 min of moderate stress by mental arithmetic with second ECG (stage 2); 5-min VR session 2 (active or sham, different to the one received during Visit 1) with third ECG (stage 3); 5-min ECG after VR intervention, STAI assessment (stage 4)

Figure 3

Between-subject interaction effects from the ANOVA output. A – Exposure sequence and the sequence of immersion events did not influence ∆HF-HRV; B – significant increase in parasympathetic activity after a 5-minute exposure to investigational device (headset A) but not sham device (headset B) compared to stress, as shown by HF-HRV

Figure 4

Changes in situational anxiety levels after a 5-minute VR exposure for the investigational device (headset A) and the sham device (headset B): A – changes of root mean square of successive differences between normal heartbeats (RMSSD), ms, B – changes of low-frequency to high-frequency (LF/HF) HRV components, C – changes of the standard deviation of the IBI of normal sinus beats (SDNN), ms, D – total power of HRV, ms², E – changes of the heart rate, F – changes of the STAI scores