FitBit exercise/activity calories include BMR but BMR portion not deducted in Cronometer

edited May 2022 in Ask An Expert

I understand FitBit calorie calculations for an exercise actually include BMR. It would seem to me that because Cronometer already accounts for BMR calories the BMR portion of the exercise entry would therefore need to be deducted from the calories synced in Cronometer. For example: my BMR = 66kcal/hr. If I do an exercise activity for one hour and FitBit estimates say 500kcal that would be 444kcal for the actual exercise itself and 66kcal being due to my BMR. So, I would expect 444kcal to be the number that should be input to Cronometer. But this is not what happens, instead the full 500kcal is recorded thus it seems to me it's doubling up on the BMR calories for that one hour exercise period.

Is my thinking correct on this or is there something I'm not understanding?


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    If you set your activity level to sedentary, crono won't adjust for your BMR and the numbers work out pretty good.

    "I've never considered excessive sanity a virtue" Mike Uris, San Antonio Express-News, 2002

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    I have crono activity set to 'none' which I believe is the correct thing to do when sync'd to a fitness tracker that provides both exercise activity data and general activity data. And unless someone can enlighten me furthehr I still believe Crono should deduct the BMR value from the BMR inclusive calorie numbers provided by FitBit.

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    I have the same concern. I ride a bike, have a power meter, and Garmin 1030 Plus. Although Garmin (as well as Training Peaks) can determine the actual amount of kJ (work) performed during a ride based upon the watts I rode, the total calories that Garmin Connect sends to Crono also includes "resting calories".

    For example, I rode an easy pace for 2 hours today and that resulted in 788 kJ of energy burned based upon the power I rode at, but then Garmin added another 111 "resting calories" and send a total of 898 calories burned to Crono.

    I have my activity level in Crono set to "Sedentary" because I don't wear any type of fitness tracker when I'm not exercising. When an exercise is added to Crono, Crono with reduce my "Activity" calories (those added due to my "Sedentary" activity level) so as to not double-count calories.

    But Crono does nothing to reduce my BMR total due to the exercise activity. The 111 "resting calories" included in the total sent by Garmin Connect for a 2 hour activity should then result in a 2 hours worth reduction in my BMR total for the day (which would be roughly a reduction of 100 calories).

    Since Crono doesn't adjust my BMR, I've stopped having Garmin Connect send my data for Crono (the 898 calories in my example above) and I instead just manually add a exercise with a 2 hour duration and 788 calories (again, using my example above).

    I'd like someone from Crono to explain the rationale for not adjusting the BMR when exercise is added that includes total calories.

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    One work-around that I came up with was to create a "food" that I call BMR calorie adjustment. I calculated what my BMR/minute value was (BMR/1440) so that when I enter this "food" I enter in the number of minutes taken for that particular workout. So, if I run for say 60 minutes my FitBit sync's 670kcal. I then enter my BMR calorie adjustment with the value 60 and it adds 64.8kcal, essentially offsetting the 60 minutes of BMR that was included in the run calories.

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    That works also.

    Would really like to get a response from Crono as to their rationale for not automatically reducing BMR to eliminate the double-counting - since they do acknowledge the double-counting issue with exercise and Activity Level calories and take action there.

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