The Garmin Connect app syncs my runs to my Apple Watch (although it's always called an outdoor run and I can't change it to indoor), but not my calories. I ran 3 miles and it recorded 37 calories; not even active calories. The Garmin watch (FR 225) shows I burned over 300 calories. If I run on the treadmill with both, it doubles my activity time (1 hour instead of 27 minutes). Apple is replacing my watch for other reasons, but I'm not sure this is a hardware or software issue.