4Features
Starting costs nothing. The pacer and the sound stay free forever, with or without a strap.
Training
Resonance workshop
Six rungs from 7.5 to 5.0 a minute in a shuffled order, with adaptive fine-tuning when the peak sits between two rungs.
Four patterns
Free training at your rate, a morning reading that paces nothing, a short priming pattern, a long recovery one.
The sound
Two distinct notes with an audible turn, deliberately dark. Keeps running with the screen locked, over headphones or the speaker.
Fine adjustment
Inhale and exhale in tenths of a second, a pause, session length. The 40:60 ratio is the default, not a law.
Measurement
Any Bluetooth chest strap
No hardware of ours, no accessory to buy. On connecting, the app tells you whether your sensor sends beat intervals or only a pulse.
Signal quality in the open
The share of corrected beats appears in every reading. When it was too high nothing is graded, rather than showing a figure nobody could compare.
After a session
Figures with provenance
RMSSD, SDNN, pNN50, LF/HF, swing, peak frequency. Each with a reference range, and underneath it says where that range came from.
Explicit refusal
Figures a grade would mislead get none, and one sentence saying why not. The figure itself stays at full size.
One next step
From your own numbers, not from a stock programme. Exactly one, every time.
History and trends
Small multiples per figure and comparisons over weeks. A trend appears only once there are enough sessions to claim one.
On your iPhone
Apple Health
Mindful minutes from every session. SDNN if you want it, and the app tells you that paced breathing lifts that figure and can shift your baseline in other apps.
Backup and export
Your history can be saved to a file and read back. It also sits as a readable file in the Files app.
What it costs
The pacer, the sound and the workshop are free. So are the readings at the start. Anyone who keeps at it for weeks is asked about a subscription, and the written coaching and the trends move behind it. Access to the app itself stays.