I have an Apple Watch. So does my wife. Most of our friends do. And for years I had the same nagging frustration every morning: the watch would show me my HRV trend on the Health app and I would stare at it, thinking — okay, this is going down. What am I supposed to do about it?
Every wellness app I tried gave me the same shape of answer: do more of the app. Meditate. Listen to a guided session. Try the sleep stories. None of them ever told me whether what I just did actually moved the number. The whole industry had agreed to treat measurement and intervention as separate businesses.
Meanwhile, the physiology had been settled for decades. Slow breathing at the body’s resonance frequency — about six breaths per minute — measurably raises HRV. Paul Lehrer at Rutgers had been publishing on this since the 1990s. Andrew Huberman rediscovered it in 2023 with the physiological-sigh paper. Olympic teams have been using it. PTSD therapists have been using it. Asthma researchers, anxiety clinicians, cardiologists.
And consumer apps were ignoring all of it.
The wedge nobody else was going for
I built HRV Breathe to close the loop. Read the HRV before the session. Read it after. Show me the delta. That was the brief. The whole rest of the app — the techniques, the programs, the visuals, the Apple Watch app — exists to support that one moment on the completion screen.
Every breathing app on the App Store asks you to take it on faith that it’s working. HRV Breathe asks Apple Health.
That’s the wedge. It sounds small. It is actually enormous. A measurable signal of efficacy changes the relationship between user and product from “here’s a thing you should try” to “here’s a thing you can verify.”
Why no Android version
Because Apple Health on iOS plus HRV on Apple Watch is the only mature mobile HRV pipeline I trust. Google Fit’s HRV story is partial. Wear OS HRV varies wildly by device manufacturer. Samsung’s Health Platform has different metrics. The equivalent of “read the most recent SDNN sample from the system health store” doesn’t exist as cleanly on Android, and the polyfills are leaky.
I’d rather build one app that does the measurement correctly than two apps that paper over the rough spots. There’s an email signup in the footer if you want to be told when that changes.
Made by two people
HRV Breathe is built by SUUR — a husband-and-wife indie studio in Fort Collins, Colorado. The same people sweat the typography, the haptic curves, the App Store screenshots, the customer emails, and the science citations. There is no funding round. There is no growth team. The whole product is the same scale as the trust we’re asking you to extend.
We chose dark-only because it felt right. We chose Cormorant Garamond italic because we wanted the headline to feel like a line in a book, not a slide in a deck. We chose to never run an analytics script over your HRV because the moment we did, we could no longer say we don’t see it. None of these were committee decisions.
If you try it and have feedback, the email is hrv@suur.io. The person reading it built the app.