Hi
If you have followed the steps here to pair and set up your Apple Watch:
Set up your Apple Watch - Apple Support
And if you have set up the Activity app:
Track daily activity
Then Health and Activity data should sync automatically from your Apple Watch to the Activity app and Health app on your paired iPhone:
If it is not doing so, then the following steps may help:
If you have not yet done so, update your iPhone and Apple Watch with any available software updates, starting with your iPhone (begin by making a backup):
On your iPhone, go to: Settings > Privacy > Motion & Fitness - check that both Fitness Tracking and Health are enabled.
On your iPhone, in the Watch app, go to: My Watch > Privacy > check that both Fitness Tracking and Heart Rate are enabled.
Check that Wrist Detection is turned on and that, if passcode is enabled, you are unlocking your Apple Watch after placing it on your wrist:
- On your iPhone, in the Watch app, go to: My Watch (tab) > Passcode > check that Wrist Detection is turned on.
Close certain apps and then restart (normally) both your iPhone and your Apple Watch:
- Close the Watch app, Activity app and Health app (if open) on your iPhone:
- Double-click the Home button, then swipe up on each app preview to close the apps.
- Turn both devices off together, then restart your iPhone first:
Follow the further instructions here, if necessary including unpairing and re-pairing your Apple Watch:
If the issue persists, then you may wish follow the steps below, which have resolved Activity data syncing issues for other users.
Important: note that this process involves the permanent loss of all sensitive data on your iPhone and Apple Watch, including historic Health and Activity data, HomeKit data and saved passwords.
Start by making an unencrypted backup of your iPhone:
Restore your iPhone as new (ie to factory settings) using iTunes:
After the Restore completes, during setup, restore your iPhone from the unencrypted backup:
Pair your Apple Watch, setting it up as a new watch (do not restore it from backup):