Daily Activity Summary Data Definition Questions

[sleepy_dave]

I am currently pulling data from Daily Activity Summary (https://dev.fitbit.com/build/reference/web-api/activity/) and have several questions about the following fields:

• activityCalories: Per the documentation, this field includes BMR calories. Is there a way to obtain just calories burned due to activities? Or a way to obtain the number of minutes in activities and then subtract out the appropriate number of BMR calories?
• caloriesOut: What does this field represent? If it is the sum of activity calories and BMR calories, are BMR calories being double counted since activity calories also include BMR calories?
• activeScore: What does this field represent?
• elevation: What does this field represent? What are the units?
• floors: What does this field represent? What are the units?
• marginalCalories: What does this field represent?
• lightlyActiveMinutes: What does this field represent? How is “lightly active” determined?
• fairlyActiveMinutes: What does this field represent? How is “fairly active” determined?
• sedentaryMinutes: What does this field represent? How is “sedentary” determined?
• veryActiveMinutes: What does this field represent? How is “very active” determined?

[sswift]

Why aren't there data dictionaries for these? I've seen requests since 2016

[JohnFitbit]

Hi @sleepy_dave,

Apologies for the very late response.

• The activityCalories element will provide you with the number of calories burned during the day for periods of time when the user was active above the sedentary level, in other words, during an activity. This value is calculated minute by minute for minutes that fall under this criteria. 
• The caloriesOut element is the total sum of activityCalories + caloriesBMR.
• The floors element is defined as the equivalent floors climbed. To see how floors are recorded, see our help article here: https://help.fitbit.com/articles/en_US/Help_article/1141.htm?Highlight=floors
• Sedentary, Light, Fairly, and Very Active, minutes can be defined as the following metabolic equivalent of tasks (METs) for each level of activity: (Source https://en.wikipedia.org/wiki/Metabolic_equivalent_of_task)
  • Sedentary: Activities less than 1.5 METs
  • Light: Activities less than 3 METs
  • Fairly/Moderate: Activities between 3 - 6 METs
  • Very: Activities greater than 6 METs

@sswift Thanks for the suggestion, we are aware that this is a widely requested item and is being considered.

I hope this helps. Please let me know if you have any other questions.

[ammulder]

I've been searching for the same thing, and @JohnFitbit I appreciate your response here, but it doesn't seem to be accurate.  Here's what the Fitbit Activity API reports for me for yesterday (omitting other fields):

https://api.fitbit.com/1/user/-/activities/date/YYYY-MM-DD.json

"summary": {
    "activityCalories": 3468,
    "caloriesBMR": 1774,
    "caloriesOut": 4601,
    "marginalCalories": 2320
}

Clearly the caloriesOut element is NOT the total sum of activityCalories + caloriesBMR (which would be 5242 not 4601).  For what it's worth I didn't manually log anything, all the data is from my tracker, though I also didn't start/stop activities on the tracker, so the activities it captured were just ones it deduced from the data.

I've also not found a definition for marginalCalories.

[Gordon-C]

Hi @ammulder 

Let me double-check with engineering on this.   While the generalized calculation is caloriesOut = caloriesBMR + activityCalories, it's possible our internal algorithms changes a bit.

I don't have any historical information on what marginalCalories is.   We did research this topic last year and worked with our research and engineering teams, but couldn't come up with a concrete answer at the time.   I can look into it again.

[ammulder]

Hi @Gordon-C , were you able to get a response from engineering?

I had to laugh a little, thinking, we're all developers here, maybe you can just post the code!  😉

[samspisiak]

Any updates here @Gordon-C ?

[andyreagan]

@Gordon-C @ammulder I also would love to have an answer here. The four calories summaries don't add up in any obvious way.

[andyreagan]

I searched the forum for "marginalCalories", and I see a post elsewhere that this field is deprecated and should be ignored.

https://community.fitbit.com/t5/Web-API-Development/Calories-values-in-the-getActivity-API-call/m-p/...

• Same question that doesn't get an answer on marginalCalories: https://community.fitbit.com/t5/Web-API-Development/What-do-the-calorie-fields-actually-represent/m-...
• Similar question, no answer on marginalCalories: https://community.fitbit.com/t5/Web-API-Development/Calories-from-steps/m-p/974268
• Same question, no answer at all: https://community.fitbit.com/t5/Web-API-Development/Active-energy-derivation/m-p/1317045