4How it works
Resonance breathing is training, not treatment. You breathe slowly at a rate that suits you, and your heart swings with it more strongly than at any other rate.
Put on a strap
Any Bluetooth chest strap that sends the time between beats. Polar H10 and H9, Wahoo Tickr, Garmin HRM, Coospo. Pair once, and it reconnects on its own after that.
Run the ladder
Six rungs between 7.5 and 5.0 breaths a minute, two minutes each, in a shuffled order. What gets measured is the rung at which your heart rate swings widest.
Shuffled, because the first segment of a run reads systematically high. In a fixed order the same rung would collect that bonus every time.
Train at your rate
Inhale and exhale are two distinct notes with an audible turn between them. Close your eyes, put the phone down. Ten minutes is usual, five is a complete session.
Read what happened
Every figure with its reference range and where that range came from. What cannot honestly be graded is not graded, and the app says why.
One thing for next time
Exactly one, every time. Usually about technique: smaller breaths, follow the tone to the end, same posture as when you were measured.
How often, and for how long
Once a day, five days a week, is a good frame. After three to four weeks something can be said about your technique for the first time.
What we will not promise: that practising more does more. There is no evidence for it, and in one controlled comparison five minutes did as much as twenty.
What this is not
Not a medical device, not a diagnosis, not a treatment. We do not claim it raises your resting HRV or lowers your blood pressure, because the best-powered studies of both found nothing.
What can be said: you get measurably better at it, and that is the point.