Map My Fitness calories far too low

stampz
stampz Posts: 6 Member
edited November 2024 in Fitness and Exercise
Hi all,

Wandered if anyone has any opinion on why I would be seeing really low exercise calories on Map My Fitness.

As an example, I went out on a 13 mile bike ride this morning wearing my HRM. It took me about 75 mins and I rode roughly at 10mph, my HRM (I suspect correctly) said I had burnt 642kcals which feels about right.

However Map My Fitness said I only burnt 155kcal! Which is obviously far too low.

My settings for weight/height are correct on map my fitness.

Anyone got any ideas?

Replies

  • stampz
    stampz Posts: 6 Member
    anyone?
  • lemonsnowdrop
    lemonsnowdrop Posts: 1,298 Member
    I dunno, it tends to overestimate my burns. According to my HRM, I burned 315 calories on my morning run, but Map My Run said 378. -shrug-
  • robinmarkz
    robinmarkz Posts: 93 Member
    That does sound low for 13 mile ride. It was a long ride at a more leisurely pace, but it sounds low for their calculation methodology. Uninstall and reinstall the app. Also, use Map My Ride, specifically.

    I also found an RPM gadget from Wahoo that attaches to either your foot and the bike and sends information to the Wahoo app. Which connects to MFP. You can also be wearing a heart monitor (a Wahoo one would probably work better with their app) at the same time. The gadget works for all bikes. Stationary, road, recumbent road or stationery, etc. Their app also connects with MFP.

    But the main thing is that it is unusual for it to underestimate. Uninstall and reinstall the app, and use Map My Ride.

    Best,
    Robin
    P.S. -- It doesn't overestimate; it uses a formula that includes Resting Metabolic Rate to the total burn. This is called Corrected METS in the Compendium of physical activities.
  • bwogilvie
    bwogilvie Posts: 2,130 Member
    The calculator over at BikeCalculator.com estimates that you would have burned about 206 kcal for that ride, or 2.64 kcal/minute, assuming a 182-lb. rider, a 25-lb. bike, riding on the bar tops or a flat bar, cycling 10 mph for 78 minutes on flat terrain, with clincher tires. It estimates that your power output would be 46 watts. The calorie burn is on top of basal metabolism, so it's just the energy required to move the bike at that speed for that distance, with those assumptions—and the further assumption that a cyclist's efficiency is 25%. If you go toward the lower end of the usual efficiency range, say 20%, it would mean a burn closer to 250 kcal.

    Cycling is remarkably efficient, and at 10 mph, you don't have much wind resistance to deal with. Just for comparison's sake, the calculator estimates 343 kcal burned on the same course at 15 mph (6.60 kcal/minute), with a power output of 115 watts.

    And if you're on rolling hills, the energy requirement will go up significantly.

    My old Timex and Sigma HRMs grossly overestimated the energy I burned in cycling. My Garmin Edge 800, which uses not only heart-rate data but also fitness level, speed, and elevation change to estimate kcals burned, produces a lower number that's usually pretty close to the BikeCalculator value on flat terrain with no wind.
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