Drop in activity calories

My active calorie count has dropped quite a lot within the last couple of months. The exact same ride of 50 k was 1200 kcal 50 days ago and 800 today. I use the same watch (fenix 5 plus) and the same garmin HR strap. HR was 152 last time and 155 today. The same thing goes for my runs.

0 trux over 1 year ago

What was your Resting HR before the change, and what is it now? See it at https://connect.garmin.com/modern/report/60/wellness/last_year

If no significant change there, did not you change your personal body data (weight, height, age, gender) inadvertently?

If not, please post some data demonstrating the change more clearly - for example share two comparable activities from before and a recent one, showing a big discrepancy.