Support

Write to [email protected]. A person answers, usually within two working days.

Which sensors work?

Any Bluetooth heart rate monitor that sends the time between beats. Tested with the Polar H10. Also suitable: Polar H9, Wahoo Tickr, Garmin HRM, Coospo H6 and H808S.

Fitness bands and most smartwatches send a pulse only, not beat intervals, and variability cannot be computed from that. After connecting, the app tells you which kind of data is arriving.

The strap is not found

A strap only transmits once the electrodes are damp and against skin. Put it on, wet the contact areas, then search again. A strap pairs with one device at a time, so disconnect it in other apps or on your watch first.

Why are my numbers different from another app?

Because most apps measure at rest and 4-6 measures during guided slow breathing. That is not a fault, it is the point: slow breathing raises variability substantially. Compare your sessions with your own earlier ones rather than with resting values or population tables.

Why does the app refuse to grade some values?

Because a grade would mislead. LF/HF is not a stress ratio when the breathing itself sits in the LF band. SDNN is established for 24 hour recordings, not for ten minutes. In those cases the app shows the value and says why it will not rate it.

My subscription is gone

Settings, then "Restore". The subscription belongs to your Apple ID and works on any device signed in with it. You manage and cancel it in the iOS settings under your name.

Refunds

Apple handles purchases and subscriptions, and therefore refunds: reportaproblem.apple.com. Write to us anyway if something did not work. We would like to know.

My data

Everything stays on your iPhone and there is no account. The details are in the privacy policy. Settings lets you save your history to a file and read it back.