Via apple health
Method 1: Use the Zwift app directly with iPhone
Install the Zwift app on your iPhone and Apple Watch.
Open the Zwift app on your iPhone, log in or sign up.
On the paired devices screen , pair your smart trainer. Then select the heart rate icon, and your Apple Watch should appear as an option. Select your watch.
Enable access to health data on your iPhone when prompted, allowing all health categories.
Open the Zwift app on your Apple Watch and start your activity. Your heart rate and other data should appear on both of your devices.
Method 2: Use the Zwift Companion (ZC) app to connect to other devices
Install the Zwift Companion app on your iPhone and Apple Watch.
Open the Zwift app on the device you want to use it on (iPad, PC, Mac, or Apple TV) and go to the paired devices screen.
Open the Zwift Companion app on your iPhone and Apple Watch. Wait a few seconds for everything to sync over your Wi-Fi network. Once synced, the Zwift Companion app on your iPhone will display a map-style view.
Select the heart rate icon on the Zwift Companion app, and your Apple Watch should appear. Select your watch to start displaying your heart rate.
If you're having trouble connecting, make sure Bluetooth is turned on on your iPhone, health data access for Zwift is turned on in the Health app, and consider restarting your devices if necessary .
It's important to note that using the Apple Watch for heart rate with Zwift may not be as accurate as using a dedicated heart rate strap. However, for many users, the convenience and easy integration with Apple Health outweighs this potential difference in accuracy.
For those looking to sync their Zwift activities with Apple Health without directly using the Zwift app or Zwift Companion, there are third-party solutions like RunGap, which allows Zwift workouts to be synced with multiple platforms, including Apple Health.
For more information and details on setup and troubleshooting, I recommend checking out the Zwift community guides and forums, where you can find additional tips and solutions to common issues.
Via google fit
To sync Zwift with Google Fit, a direct method is not available as Google Fit does not appear to offer options to directly link to other devices or apps like Zwift. A popular alternative is to use Strava as an intermediary to sync activities from Zwift to Google Fit, although certain types of activities like static rides may not be pushed to Google Fit via Strava.