Active Calories available yet?

Do the latest versions of ConnectIQ support the ability to display Active Calories on a watch face. I know previously this was not available and the only option would be to try to calculate it?

If not, then what is the best mechanism to request Garmin consider adding it?

thanks


TheSalamander

  • I tried doing this recently for a watchface, but had to calculate it myself doing something like this:

    var userProfile = UserProfile.getProfile();
    var BMR = (10.0/1000.0)*userProfile.weight + 6.25*userProfile.height - 5.0*(dateInfoMedium.year-userProfile.birthYear) + ((userProfile.gender==1/*GENDER_MALE*/)?5:(-161));
    var nonActiveCalories = (BMR*1.2).toNumber();
    var activeCalories = getNullCheckZero(activityMonitorInfo.calories) - (nonActiveCalories * timeNowInMinutesToday) / (24*60);
    var eStr = "" + ((activeCalories<0) ? "--" : activeCalories);

    Using the Mifflin-St. Jeor equation for BMR.

    Unfortunately I then realised because the calculation of BMR is different from what Garmin use the active calories is slightly different from the value displayed in Garmins widget.

    So then I tried all the other BMR calculations I could find including Harris-Benedict & Revised Harris-Benedict but none of them match Garmins calculation.

    I then started doing some tests to reverse engineer Garmins calculation assuming they use something of the form: k + x*age + y*height + z*weight = cal and I believe it is possible to calculate those constants to get an exact match! It's on my todo list, but I haven't got around to it yet.

    My plan is to get some sample values from the Garmin calories widget for various values of user age, height & weight, at exactly 12:00 midday (so exactly half the calories of 24 hours), and then use those values to finish reverse engineering the constants as accurately as I can.

    Looking at my old notes I think the initial rough calculations for "Garmin BMR calories" gave (for a male):

    x=-6.1, y=7.6, z=12.1, k=9

    But been a while so I could easily be mis-reading my notes Slight smile

  • I've done some extra calculations now and this seems closer:

    Garmin 24 hour resting calories = 5.0 - 6.12*age + 7.63*height + 12.2*weight

    Posting further info in this other thread now: forums.garmin.com/.../978952

  • I found that the calculation is more accurate if you use age in months/12 to account for fractional parts of the year.

    If you look at the formula, if you are off by 11 months, then 11/12*6 = 5.5 calories error.  But unfortunately the API doesn't give access to the user's birth month.