If your wearable or smart scale isn't syncing to Apple Health, reThrive can't access the data. This guide helps you troubleshoot device-to-Apple Health sync issues.
Confirm the problem
First, check where the sync is failing:
Step 1: Check your device's companion app
Open your wearable or scale's app and see if recent data appears there.
Step 2: Check Apple Health
Open Apple Health
Tap Browse
Select a metric your device tracks (e.g., Resting Heart Rate)
Look for recent data points
If data is in the device app but not Apple Health: Follow this guide.
If data is in Apple Health but not reThrive: See Apple Health sync issues instead.
Device sync fixes by brand
Apple Watch
Apple Watch syncs continuously and automatically to Apple Health on your paired iPhone.
If data isn't appearing:
Make sure your iPhone and Apple Watch are nearby
Open the Watch app on iPhone
Check that Bluetooth is enabled on both devices
Force a sync by opening any Apple Watch app on your iPhone
Check Apple Health again
Force restart if needed:
iPhone: Volume up, volume down, hold side button
Apple Watch: Hold side button + Digital Crown for 10 seconds
Garmin, Oura, Fitbit, Polar, Whoop, Withings
These devices sync through their companion apps, which then write to Apple Health.
Step 1: Make sure the companion app is installed and logged in
Download the official app if you haven't
Log in with your account
Make sure the app can see your latest data
Step 2: Enable Apple Health sync in the companion app
Each app has different settings:
Garmin Connect: Settings > Permissions > Apple Health > Enable
Oura: Settings > Apple Health > Enable sync
Fitbit: Profile > Apps > Apple Health > Connect
Polar Flow: Settings > Integrations > Apple Health
Withings Health Mate: Profile > Apple Health > Activate
Step 3: Grant write permissions to the companion app
Open Apple Health
Tap your profile picture (top right)
Tap Apps under Privacy
Select your device's companion app
Toggle on the metrics you want to sync
Step 4: Force a sync
Open the companion app
Pull to refresh or navigate to the data tab
Wait for the sync to complete
Check Apple Health for new data
Smart scales
Smart scales sync when you step on them, then the companion app writes to Apple Health.
If readings aren't appearing:
Make sure Bluetooth is enabled on your phone
Make sure the scale's companion app is installed
Step on the scale with your phone nearby
Open the companion app to trigger a sync
Enable Apple Health sync in the scale's app (see brand-specific settings above)
Check Apple Health for Weight, Body Fat Percentage, or Lean Body Mass
Common device sync issues
Bluetooth connection problems
Make sure Bluetooth is on
Restart your phone
Re-pair the device if needed (check device app settings)
Background app refresh disabled
Go to iPhone Settings > General > Background App Refresh
Make sure it's enabled globally
Find your device's companion app and enable it
Companion app needs updating
Open App Store
Tap your profile icon
Scroll to see pending updates
Update your device's companion app
Device battery is dead
Charge your device
Some devices don't sync historical data, so you may have gaps
Low Power Mode is interfering
Low Power Mode can prevent background syncing
Disable temporarily: Settings > Battery > Low Power Mode
iCloud sync issues (Apple Watch only)
Go to iPhone Settings > [Your Name] > iCloud
Make sure Health is toggled on
Sign out and back in if needed
Verify sync is working
After trying fixes:
Open your device's companion app
Look for a sync status or last sync time
Check that it's recent (within the last few hours)
Open Apple Health and verify new data points appear
Open reThrive and trigger a sync from Settings > Apple Health
When the device works but doesn't provide all metrics
Some devices track metrics internally but don't write them to Apple Health.
Example: Garmin tracks HRV and VO2max in Garmin Connect, but doesn't write those to Apple Health.
Solution: Add readings manually or wait for reThrive's direct integrations (coming soon), which will read directly from Garmin, Oura, and other platforms.
See the compatibility table in Apple Health to understand what your device provides through Apple Health.