HRV Breathing: Recovery

HRV Breathing is a resonant breathing app built to improve heart rate variability (HRV) through slow, paced breathing.

It works on iPhone on its own, so you don't need a watch to use it. If you have an Apple Watch, you can go one step further and leave the phone out of the bedroom entirely: HRV Breathing for Apple Watch is a complete app on your wrist. The red-shifted interface is made for the dark, so it won't glare in a dim bedroom.

ON IPHONE
• A complete breathing app. No Apple Watch required.
• Guided resonant breathing at your own pace, with symmetric or longer-exhale modes.
• Set your pace and session length, and start breathing.

GO PHONE-FREE WITH APPLE WATCH
Keeping your phone out of the bedroom is one of the simplest things you can do for your sleep. That's why we built HRV Breathing for Apple Watch: you keep the breathing without the screen.
• Fully standalone. Set your pace, session length and haptics right on the watch and start a session. Your iPhone can stay in another room.
• Haptic cues on every inhale and exhale, so you can follow along with your eyes closed. Configurable haptic strength.
• Unlock once in the app. No subscription. Share it with up to six family members through Family Sharing.
• Already bought HRV Breathing? Your Apple Watch app stays unlocked. Nothing to do.
• Using both? Settings are synced both ways between the iPhone and Apple Watch apps.

WHY HRV BREATHING?
• Precision pacing: set your personal resonant frequency (4.0–7.0 bpm in 0.25 steps), the pace where HRV peaks.
• Sleep-ready design: a red-shifted interface that won't glare in a dark room. Sessions auto-save if you fall asleep mid-session.
• Private: we don't collect your data.

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, which is 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. 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., 2000). Use it however it fits you: in the morning for mental clarity, to downshift after a workout, or in the evening to help the body drift more easily into sleep. If you wake in the night, a short session can help you settle back to sleep. Set anything from 1 to 60 minutes depending on your needs.

APPLE WATCH 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 optimization and general well-being. It is not a medical device and does not diagnose, treat, or prevent any medical condition.