Vayu: Screen-Free Haptic Breathwork with HRV-Adaptive Control—Pilot Outcomes and System Design

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.