Cairn has no account, no analytics, and makes no network calls of any kind. Everything it reads or writes lives in Android Health Connect, on your device, under your control. Nothing about you or your health ever reaches us, because there's no server for it to reach.
Only when you log or edit an entry yourself — from the phone app or the watch quick-log:
Deleting an entry in Cairn deletes the matching Health Connect records with it. Nothing is retained anywhere else — there is nowhere else.
The fields above, to keep its own copy in sync with Health Connect, plus a handful of figures it displays for context but never writes itself: steps, active and total calories, exercise sessions and distance, and sleep sessions. Sleep in particular is never captured by Cairn — it's read from whatever your watch's own software already recorded.
A record-by-record account, since "your data" means different things depending which figure you mean:
* Only while continuous heart-rate monitoring is switched on, on the watch, by you.
The phone and watch talk to each other only over Wear OS's own on-device Data Layer — a weigh-in on the watch and a heart-rate batch both travel exactly as far as your own two devices, and no further.
Cairn is not directed at children and does not knowingly collect data from anyone under 13. As it collects nothing beyond your own device's Health Connect store in the first place, this is a description of behaviour, not a data-handling exception.
If Cairn's data handling ever changes, this page will change first, with the date above updated to match. Given the app's own no-network-calls design, that's expected to be rare.