The breathing app that responds to your body.

Vayu is an HRV-informed haptic breathing app. It guides your breath through gentle wrist haptics on Apple Watch and Wear OS, with no screen and no sound, then reads your heart rate variability (HRV) from the watch after each session and uses it to shape the next one. Vayu supports 68+ smartwatch models and has been downloaded 70,000+ times. Day-30 retention reached 64% in our strongest 2025 cohort.

Calm and Headspace play audio content through your phone. Vayu guides your breath through your watch and reads your physiology after each session. Calm plays a track when you open the app; Vayu paces your breathing through wrist haptics while your phone stays in your pocket, then reads your HRV from the watch and uses it to inform the next session. Calm has no HRV integration.

Vayu guides your breath through haptic taps on your Apple Watch, so you can keep your eyes closed and your phone in your pocket. After each session, Vayu reads your heart rate variability (HRV) from Apple Health and uses that reading to adapt the next session, so you can see how your HRV responds to practice over time.

Box breathing (4:4:4:4), resonance frequency breathing (5 to 6 breaths per minute), 4-7-8 breathing, Cyclic Sighing, and custom breath ratios, plus the Indian pranayama techniques Bhastrika (Bellows Breath), Kapalbhati (Skull Shining Breath), and Anulom Vilom (Alternate Nostril Breathing). Every technique is available with haptic guidance on Apple Watch and Wear OS, and your HRV is read from the watch after each session.

Resonance frequency breathing synchronizes your breath with your heart rhythm to maximize heart rate variability. The optimal rate is typically 5 to 6 breaths per minute, roughly five seconds in and five seconds out, though it varies by individual. Vayu guides resonance breathing through wrist haptics and reads your HRV after each session, so you can see how your body responds to the practice over time.

Yes. Your Apple Watch or Wear OS device guides your breath through wrist haptics on its own, and your HRV is read from the watch once the session ends. You never need to look at a screen during a session.

HRV is the variation in time between consecutive heartbeats, measured in milliseconds. Higher HRV indicates an adaptable, well-recovered nervous system; lower HRV is associated with stress, fatigue, and overtraining. Vayu reads the HRV your watch records after each session (SDNN, the figure Apple Health reports) and tracks it over time.

Yes. Vayu runs on Android phones and Wear OS watches, including Pixel Watch, Samsung Galaxy Watch, and 68+ smartwatch models in total. The iOS version supports iPhone and Apple Watch. Both guide your breath through wrist haptics and read your HRV from the watch after each session to inform the next one.