Apple Watch app never stop

When you use the Apple Watch app and another cardio system, the Apple Watch NEVER stop if you use the cardio belt.
Ride with a belt. When ride with the apple watch.
Then ride again with the belt. The apple watch will start anyway. Finish you’re ride with the belt. The Apple watch continue to capture cardio.
Restart everything. Nothing works.
The only way is to start another ride with the Apple Watch and quit without saving. Then the app finally stop.
Best regards

I am having this problem as well. After I used the Apple Watch Companion app to capture heart rate on one ride, on the next ride, it did not work, so I switched back to my Garmin HRM. Yet my Apple Watch is now stuck capturing my heart rate, and draining the battery constantly, even after I un-installed the app. I tried restarting my Apple Watch, nothing helped. I could not get it to stop draining the battery with the green LED on the back constantly on.
However, after two more watch restarts, the battery drain has finally gone away.
The Apple Watch companion app is a good idea, if only it had worked marginally better.

One solution is to restart a zwift session with the apple watch and stop the session properly.
I have the feeling that the apple watch’s app won’t stop until it received an order to stop from zwift.

Thanks - I will keep that advice in mind if I decide to give it another try. As long as I work up a little sweat, there are rarely any problems with the Garmin HRM, but it takes a while before it starts working. That’s why I wanted to check out how the Apple Watch might do the job instead.

If you put some water on the pads before putting it on it will help to have it working quicker.