@akashraletta Hey! So I think this is because I have more muscle mass than the average person with the rest of my stats. Not because I’m some kind of she-hulk but because I have been lifting for 3 years, and the average Fitbit user probably hasn’t. Obvs Fitbit doesn’t know my bf%, or at least doesn’t use it for calorie burn estimations.
We know that muscle burns more calories than fat at rest, so even if I were to become sedentary, I’d burn more calories than somebody else with my stats who hasn’t lifted weights (until my muscle started to atrophy).
Also, most of my scheduled exercise is either lifting or HIIT. I jog one 5k a week and do a pretty chilled yoga class. So for a large portion of my week I will have the small “afterburn” effect (EPOC) that you get from HIIT and lifting weights, however my heart rate would look normal and my Fitbit has no way of knowing.
When I’m lifting weights and my heart rate is in the “fat burn” range, for all my Fitbit knows I’m just walking around.
Additionally, when I’m doing HIIT my heart rate goes right up to 180+, but my Fitbit can never keep up with the intervals and records it at 115-125 for the duration of the exercise, which I know is wrong (checked with treadmill and by taking my pulse). It’s only a few minutes a week but still will contribute towards underestimated cals!
I’m not sure why it would overestimate for others, but probably a mixture of the above. Less muscle mass than average, maybe lots of steady state cardio which is notoriously difficult to calculate accurate calorie burn for but is well rewarded by Fitbit?
Tbh I don’t really know, but I have read the muscle mass theory on another thread before and it does make sense!
I have a Fitbit Alta HR btw