Hi everyone,
I’m trying to understand what seems like a major calorie overestimation during a recent walk and would appreciate some clarification from the community (or anyone from Fitbit who can provide a technical explanation).
Here are the details:
- Duration: 1 hour 30 minutes
- Pace: 12'53" per km (~4.6 km/h – moderate walking pace)
- Average heart rate: 110 bpm
- Body weight: 69 kg
The device reported approximately 700 calories burned.
Using standard MET calculations and heart rate–based expenditure models, someone of my weight walking at that pace should realistically burn somewhere around 350–450 calories, even when including resting calories.
Burning 700 calories under those conditions would imply that I was either:
- Secretly jogging,
- Hiking at a serious incline,
- Or running a metabolism worthy of academic research.
I rely on this device for training tracking and energy balance, so a potential 60–90% overestimation is not a minor discrepancy.
Can someone clarify:
- How Fitbit calculates calories during steady-state walking?
- Whether the displayed number always includes resting calories?
- Whether wrist-based HR is known to inflate calorie estimates at lower intensities?
I’m genuinely looking for a technical explanation rather than a generic response, as data accuracy is important for training purposes.
Thanks in advance.
