Since i recently went for swim training more often, i found that the optical HR sensor take about 15 minutes (!) until it catches up to the real HR.
Aside from swimming and weight lifting i use a HR strap, where this is not an issue.
The HR sensor can't be that bad, so i assume it's a software bug?
Especially since the readings always get to the correct level after 14...16 minutes, this seems to be systematic.
The workouts below all had a constant load from the beginning, so this is not about the HR slowly ramping up.
This is really annoying, since it messes up the whole training statistics, which is completely based on the HR.
Garmin-Sierra When will this issue get fixed?
