Issues with heart rate monitor (green lights)

Hi

The green LEDs are used by the heart rate sensor. It is normal for the sensor to take measurements continuously during workouts, but they should not otherwise remain permanently lit.

If the LEDs are permanently lit, then you may have a workout or other fitness-based session (via a third-party app) in progress (there may also be a runner icon on your watch face).

In the Workout app - and also any third-party fitness tracking app that you may have installed - be sure to end any workout that is currently paused or in progress:

• Work out with your Apple Watch - Apple Support
• End and review your workout

If the LEDs remain lit after ending any active workout, then it may help to close certain apps and then to 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.

• Close the Workout app, Activity app and Heart Rate app on your Apple Watch:

  If an app unexpectedly quits, stops responding, or won’t open - Apple Support

• Turn both devices off together, then restart your iPhone first:
  • Restart your iPhone, iPad, or iPod touch - Apple Support
  • Restart your Apple Watch - Apple Support

Also be sure to use your Apple Watch in accordance with Apple's handling guidelines in respect of operating temperatures:

Keep Apple Watch within acceptable operating temperatures - Apple Support

If the issue persists or recurs, then it may help to unpair and re-pair your Apple Watch:

• The Watch app on your iPhone takes a backup of your watch automatically when unpairing via the app.
• Initially choose to Restore from Backup during set up (most data and settings will be restored, with some exceptions, such as Apple Pay cards, passcode).
• If the issue persists, consider instead unpairing and setting it up as a new watch.
• Unpair your Apple Watch and iPhone - Apple Support
• Set up your Apple Watch - Apple Support

If the issue then still persists or recurs, then your Apple Watch may require service. I suggest that you contact Apple Support (remote diagnostics and/or mail-in service may be available, if required), make a Genius Bar reservation or visit an Apple Authorised Service Provider for assistance:

• US: Apple Watch Service Answer Center - Apple Support
• Elsewhere: Apple - Support

Have you checked if a workout is still active in the Workout app on Apple Watch? During workouts, the heart rate sensor is always on. Otherwise it may be a watchOS glitch and I would suggest turning your Apple Watch off and on again. I've had to do this on mine once in a while when the battery was draining faster than expected.

You're most welcome! 🙂