Nonsense Calorie Numbers From Map My Fitness Apps

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don9992
don9992 Posts: 49 Member
in Fitness and Exercise
This was discussed briefly elsewhere but I think it warrants a thread of its own.

I've used Map My Ride as a bike computer for several years now. Aside from sucking my phone battery dry by hitting the fully-lit display, the GPS, and constantly communicating with the Internet, it's easy to read while riding and records the workout to the cloud. I also have a Polar HRM watch running on the handlebars next to it to watch my heart rate.

While the calorie burn numbers I get from Polar are always more conservative than those from MMR, the discrepancy after a 30-mile road bike ride on Friday was pretty excessive: 1242 from Polar, over 2400 from MMR.

When I compare that result to what I see when I use MMR to track walking, it is marginally higher than Polar (either side of 600 for a four miler).

I have a theory about why this is:

If you've ever looked at all the Map My Fitness family of apps (Ride, Walk, Run, Dog Walk, etc.) you'll notice that, color scheme aside, they appear to be exactly the same app. I suspect the algorithm for calculating calories is the same as well and my suspicion is that it's based on running.

That would mean it based the calorie calculation on the idea that I ran 30 miles at an average speed of 15MPH on Friday. If that's the case, it's pretty understandable that it would think I was burning insane numbers of calories. That said, understandable is not very acceptable.

While I've heard Strava is more accurate with calorie burn numbers, I will probably stay with MMR for mapping and mileage calculations and take Polar's calorie numbers but I would warn anybody using an MMF product for cycling to take their calorie numbers with a grain -make that a block - of salt.

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  • sijomial
    sijomial Posts: 19,811 Member
    edited April 2017
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    That's an interesting theory!
    Do agree that MapMyRide gives ridiculous calorie estimates.

    Having just logged 2174 calories for 73 miles today the thought of over 2400 for 30 miles is a bit jaw-dropping.

    I found it very useful to "calibrate myself" on a power meter equipped trainer. It really gave me a pretty reasonable idea of different levels of perceived exertion and heart rate relating to approximate calorie burns.
    On short fast rides (time trial style) 700+ for an hour is pushing to my limit, 600/hr for fast two hour rides and c. 500/hr for long steady rides like today.

    Strava works quite well for me in terms of estimates. A bit more consistent than Garmin.
    When I used a Polar HRM custom calibrated with my personal HR range and VO2 max settings it was also pretty reasonable.
  • liddyb
    liddyb Posts: 1 Member
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    I hiked for 7 miles in about 3.5 hours, and it told me I had burned over 2500 calories (I estimate that is at least double what I actually burned). It seems much more accurate when I set it to walking however.
  • columbus2015
    columbus2015 Posts: 51 Member
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    Strava definitely seems to be the most conservative estimate for calories; I tend to believe it, even though it doesn't see wind direction/speed which can make a huge difference on a bike.

    I've never understood why so many apps (and devices like exercise bikes, etc) grossly overestimate calorie burn. Its like they're trying to set people up by giving them false data...
  • TimothyFish
    TimothyFish Posts: 4,925 Member
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    I haven't used the Map My Ride app since they quit updating it for Windows Phone. When I was using it, I calibrated it by telling the app that I weighed several pounds less than I did.
  • heybales
    heybales Posts: 18,842 Member
    edited April 2017
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    I know they aren't basing the bike on running formula's - it would be a whole lot more than even what you got.

    http://www.exrx.net/Calculators/WalkRunMETs.html

    Strava for me was very bad, because wind was never a factor for them when it really was for me, and I almost always ride alone. (sounds like song lyrics).
    I also examined their calculations on incline, way off for my rolling type terrain.
    Starting at say 100 feet, dropping to 50, going to 75, dropping to 50, going to 125 - was given an incline of 25 feet over that distance and used in the calculation. If that was the extent of the rolling terrain in a longish distance, perhaps not bad, but repeat that massively for 30 miles and their math is now way off.

    Powermeter confirmed how badly it underestimated in all situations.

    Ditto to Polar (or rather a Polar funded study formula) with correct stats matching the power meter. Garmin decently close but their formula a tad different.

    Shoot, even SportTracks with proper bike/accessory/clothes weight and body weight was decently close - they only missed the wind factor.
    And sometimes an out & back would fairly balance out the wind (rarely it seems).

    I'm wondering if you are seeing something that Fitbit had a problem with for awhile as a bug.

    Despite the weight being visible correctly - it was actually using KG's instead of lbs behind the scenes.
    For the calculations it probably had to anyway, but for those I got numbers from, they clearly had their entered and visible weight in lbs being used in calculations as kg's. And 170 kg's in walking/running/biking calculations really inflates.

    Solution was merely changing it, and entering it again.

    Is your Polar a nice unit with self-test and optional VO2max fields, or the simple units with age, gender, height, weight only?
    Cheaper can be badly off too depending on your fitness level and if BMI is bad for your age, gender.

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