HRV Breathing: Recovery

HRV Breathing is a resonant breathing app designed to improve heart rate variability (HRV) through slow, paced breathing. The app is optimised for night-time breathing, with a red-shifted display that minimises blue light for minimal disruption of the circadian rhythm.

WHY IT'S DIFFERENT
• Precision pacing: dial in your personal resonant frequency (4.0–7.0 bpm in 0.25 steps), the pace where HRV peaks.
• 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.
• Private: we don't collect your data. Breathing practice logs as an ordinary Apple Watch session.
• Pay once: a one-time price, no subscription.

THE SCIENCE
Slow, regular "resonant" breathing — around 5–6 breaths per minute for most adults — is the rhythm linked to peak heart rate variability (HRV). Breathing at your personal resonant frequency has been shown to shift autonomic balance toward the parasympathetic ("rest-and-digest") branch and to reduce stress while increasing HRV (Lehrer et al., 2000; Fisher & Lehrer, 2022). A longer exhale deepens the parasympathetic shift — useful after hard training or a high-stress day.

FIND YOUR RATE
Everyone's resonant frequency is slightly different — typically 4.5–6.5 breaths per minute. Taller, more muscular people tend lower; smaller-framed people higher. HRV Breathing is adjustable from 4.0 to 7.0 bpm in 0.25 steps so you can pinpoint your own resonance. If you feel strained or lightheaded, the pace is too slow for you.

HOW LONG?
Aim for around 20 minutes — the dose most studied for HRV benefit (Lehrer et al.). Use it however fits your recovery: in the morning for cognitive clarity, post-workout for parasympathetic downshift, or in the evening to help the body drift more easily into sleep. Run the full 20-minute session, or set anything up to 60 minutes.

FEATURES
• Resonant pacing, configurable 4.0–7.0 bpm in 0.25 steps
• Symmetric or longer-exhale (asymmetric) modes
• Adjustable session length and haptic strength
• Red-shifted, low-blue-light night display for evening use
• Auto-save if you fall asleep mid-session
• Works with Theater Mode for a fully dark screen — feel the breath as taps on your wrist

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 — you'll still feel the breath cues as taps on your wrist. Tap the screen if you want to check it.

BUILT BY A CLINICAL PSYCHOLOGIST AND AN ENGINEER
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 works in the dark, in a phone-free bedroom, with minimal disruption to your sleep.

HRV Breathing is intended for relaxation, recovery, performance optimisation and general well-being. It is not a medical device and does not diagnose, treat, or prevent any medical condition.