Apple Watch support in Zonas is not a Bluetooth trick.
The Watch has its own companion app. It starts the workout on the Watch, reads heart rate through HealthKit, and mirrors the session back to iPhone.
Setup
- Install Zonas on iPhone and Apple Watch.
- Open Zonas settings on iPhone.
- Choose
APPLE WATCHas the heart rate source. - Check that the Watch is paired and the app is installed.
- Start a workout from the Watch flow.
Zonas can also launch the Watch app for a selected workout type from the phone path.
What Runs Where
The Watch owns the workout sensor path.
It starts an HKWorkoutSession, attaches a live workout data source, reads heart rate, updates the Watch workout screen, and sends heart rate messages to the mirrored iPhone session.
The iPhone shows the mirrored workout state.
That is why this is different from a chest strap. A BLE strap broadcasts heart rate to iPhone. Apple Watch runs the workout and mirrors it.
Settings Sync
Zonas syncs settings from iPhone to Watch:
- zone mode
- max heart rate mode
- custom max heart rate
- custom boundaries
- favorites and recents
Resting heart rate and automatic max heart rate are read locally on the Watch from HealthKit, so the first zone calculation can use Watch-side health inputs.
What You See On iPhone
When the mirrored session is active, iPhone can show:
- current heart rate
- current zone
- timer
- workout type
- Live Activity or Picture-in-Picture, depending on your selected surface
If Watch data stops arriving, the iPhone status bar can warn that data is stale.
When To Use Apple Watch Mode
Use Apple Watch mode when you want to start from your wrist and do not want to wear a separate chest strap.
Use BLE Strap mode when you want a chest strap or arm band to be the heart rate source.
Common questions
Can Zonas read Apple Watch heart rate from the iPhone directly?
No. The current app uses a Watch companion workout that starts a HealthKit workout on the Watch and mirrors that session to iPhone.
Do Apple Watch zones stay in sync with iPhone?
The app syncs zone settings and favorites from iPhone to Watch through WatchConnectivity. The Watch reads its own date of birth and resting heart rate inputs locally from HealthKit.
Can I use Apple Watch and a Bluetooth strap at the same time in Zonas?
They are separate source modes. Pick BLE Strap for a chest strap or Apple Watch for the Watch companion path.
Sources
- Monitor your heart rate with Apple Watch
Apple Watch measures heart rate continuously during workouts and calculates resting heart rate values.
- startMirroringToCompanionDevice
HealthKit workout sessions can mirror from watchOS to the companion iOS app.
- View Heart Rate Zones on Apple Watch
Apple Watch has a user-facing heart rate zone model, useful context for Watch users.