Heart rate does not work
Heart rate does not work on Apple Watch. Do I need to reset?
Apple Watch
Question marked as
The first (and simplest) thing to try if something isn’t working right is to restart your Apple Watch and its paired iPhone. If necessary (device not responding), try a forced restart. Both methods can be found here:
How to restart your Apple Watch - Apple Support
Restart your iPhone - Apple Support
If that doesn't help, the next steps would be to unpair and pair your watch again and restore from the backup. This deletes all temp and corrupted files and re-indexes the file system.
Unpair and erase your Apple Watch - Apple Support
Set up your Apple Watch - Apple Support
Other than that, here are some tips for a more accurate heart rate reading.
Your heart rate. What it means, and where on Apple Watch you’ll find it. - Apple Support