Have always had issues w. Garmin wrist-based heart rate during exercise, have had a chest strap for almost two years. Now heart rate when not exercising which used to be accurate 80% of the time is now closer to 40%, since the tech is the same it has to be software. Example - just now I put on chest strap, going to run, wrist-based 96 "external heart rate monitor connected" 45.
