Hi, to add some information to the matter, I noticed that if I had “WRIST HEART RATE” disabled, it wasn’t detecting my external chest strap (a new Polar H10). I selected it to avoid interfering with the watch’s optical readings. Therefore, after enabling wrist heart rate in the exercise options, it automatically detects the strap and monitors my heart rate during exercise.
I would have to test if, after a medium-length stop during an activity, refueling, a forced pause, and restarting the activity, the heart rate recording with an external band continues… I understand that it will always be available with the optical sensor of the watch.