Vayu: Screen-Free Haptic Breathwork with HRV-Adaptive Control—Pilot Outcomes and System Design
Dhruv Adhia, Deepali Raithatha, Arron Ferguson, Philippe Pasquier
medRxiv June 24, 2026 preprint DOI: 10.64898/2026.06.08.26355230 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Naturalistic pilot |
|---|---|
| Sample size | 199 |
| Population | Adults ages 22–65 in Canada, the United States, and India |
| Intervention | HRV-adaptive pacing |
| Duration | 4–6-week intervention |
| Topics | Breathwork |
| Keywords | Journaling file system Breathing Mood Haptic technology Biofeedback Heart rate variability Assisted living Likert scale Interface matter Adverse effect Human–computer interaction Audiology Physical therapy Mobile apps |
| Key points | Vayu was associated with reduced perceived stress, lower resting heart rate, increased HRV, and mood improvements over 4–6 weeks. |
Abstract
Abstract Vayu is a mobile breathwork system comprising an iOS companion app and Apple Watch application that delivers slow, resonant breathing using screen-free haptic cues , HRV-adaptive pacing, and reflective journaling grounded in Patanjali’s five states of mind. The watchOS component provides tactile phase guidance and real-time biometric sensing (heart rate, HRV), while the iOS interface supports analytics and personalized recommendations. In a 4–6-week naturalistic pilot involving 199 adults (ages 22–65) across Canada, the United States, and India, participants engaged in daily 5–10-minute sessions guided by on-wrist haptics. Average adherence was 4.1 ± 2.3 sessions per week, with 71% of active users maintaining at least 3 sessions per week. By week four, perceived stress (PSS-10) decreased by 2.5 points, resting heart rate declined by 7.4 bpm, and HRV increased by a median of 28.6% relative to baseline, accompanied by mood improvements. No adverse events were reported. HRV metrics are derived from Apple Watch PPG-based proxies and interpreted as relative trends. These findings suggest Vayu is effective and well-tolerated, demonstrating strong engagement and early efficacy signals.