HRV Breathing
iPhone / Forme et santé
HRV Breathing is a resonant breathing app for the Apple Watch, designed for night-time use. Guided breathwork to improve sleep, HRV, and emotional regulation.
It is designed to improve heart rate variability (HRV) through slow, regular breathing. Resonant frequency breathing, also called coherent breathing or simply slow-paced breathwork, has been shown to influence autonomic nervous system activity and to reduce stress and anxiety while increasing relaxation. Around 5 to 6 breaths per minute is the rhythm linked to peak HRV for most adults.
The app is optimised for night-time breathing, with a red-shifted display that minimises blue light and minimal disruption of the circadian rhythm.
Why HRV Breathing?
- True Phone-Free Use: Fully standalone — runs natively on your watch. Leave your phone in another room and enjoy truly phone-free sleep hygiene.
- Sleep-Ready Design: A red-shifted interface minimises blue light to protect your circadian rhythm, with haptic cues on every inhale and exhale so you can follow along eyes-closed. Auto-save if you fall asleep mid-session.
- Privacy First: HRV Breathing does not collect, store, or transmit any personal data. Sessions are recorded as standard Apple Watch workouts in Health and Activity — the app itself sends nothing.
Features
- Resonant breathing, configurable from 4.0 to 7.0 bpm.
- Haptic cues for inhale/exhale — perfect for use in total darkness, with strength adjustable in Settings.
- Red-shifted display — minimal blue light, optimised for night-time use.
- Symmetric inhale/exhale or longer-exhale breathing modes. Use Longer Exhale mode during periods of high tension or sympathetic activation.
- Adjustable pace, session length, and haptic strength.
- Auto-save. If you fall asleep mid-session, the app saves your activity and shuts off on its own. Your rest stays uninterrupted.
- No data collection.
About the breathing rate
Resonant breathing is most effective at each person's individual resonant frequency — the breathing rate at which heart rate variability oscillations reach maximum amplitude. In the HRV biofeedback literature, this typically falls between 4.5 and 6.5 breaths per minute for adults, with some individuals resonating slightly below 4.5 (Fisher & Lehrer, 2022; Lehrer et al., 2000). Taller and more muscular people tend toward the lower end of the range; smaller-framed people toward the higher end. Most people have the best effect at 5 to 6 breaths per minute.
The app's extended range of 4.0 to 7.0 bpm lets you explore further to find what feels right. The breathing should feel comfortable and calming — if you feel strained, short of breath, or lightheaded, the pace is too slow for you.
A longer exhale relative to the inhale is associated with a shift toward parasympathetic activity. If you're wound up, the longer-exhale mode is usually more calming than symmetric breathing.
Tips
- Enable Haptics in Settings → Sounds & Haptics before your first session.
- For a fully dark screen, turn on Theater Mode before you start (Control Center → masks icon). The display stays dark and won't light up when you move, and you'll still feel the breath cues as taps on your wrist. Tap the screen if you want to check it.
About the developer
HRV Breathing is developed by a clinical psychologist in Norway together with a technical partner — clinically grounded on one side, solid engineering on the other. It's built around a simple idea: a breathing tool that supports sleep in a phone-free bedroom, with minimal disruption, red-shifted display, and without collecting your data.
Important Note: HRV Breathing is intended for relaxation and general well-being. It is not a medical device and does not diagnose, treat, or prevent any medical condition.
