Vayu: Screen-Free Haptic Breathwork with HRV-Adaptive Control—Pilot Outcomes and System Design
medRxiv June 24, 2026 Dhruv Adhia, Deepali Raithatha, Arron Ferguson et al.
A mobile breathwork system called Vayu, which uses an Apple Watch and iPhone app, delivers slow breathing guided by wrist-based haptic cues, adapts pacing to heart rate variability (HRV), and includes reflective journaling. In a 4–6-week pilot with 199 adults across Canada, the United States, and India, participants did daily 5–10-minute sessions. Average adherence was 4.1 sessions per week, with 71% of active users doing at least 3 sessions weekly. By week four, perceived stress decreased by 2.5 points on the PSS-10, resting heart rate fell by 7.4 bpm, and HRV increased by a median of 28.6% from baseline, along with mood improvements. No adverse events occurred. The findings suggest the system is effective and well-tolerated.