07-28-2016 08:05
07-28-2016 08:05
07-28-2016 08:17
07-28-2016 08:17
Ignore the zone, it is a generalized calculation which, like a broken analog watch, it correct every now and again. Many folks, myself included, have a MUCH higher maximum heart rate than what the 220-age forumla would predict; it sounds like you do too.
Fitbit is gradually coming around to that way of thinking as well as just this spring they created a new feature to allow you to change your maximum heart rate, which by extension will also raise the heart rates for the various zones. In your personal settings simply bump up your max heart rate to a number a bit higher than what you've observed on your runs.