Why the vast difference in calories burned totals?

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Queen2day
Queen2day Posts: 68 Member
in Fitness and Exercise
I just completed walking a little over 2 miles at an average speed of 3.0 MPH, I did use my new HRM [Polar RS100] which said I burned 222 calories for the 43 minutes I was walking. I also had my iPhone app, which is partnered with this site, which said the calorie burn was 765, and then MFP shows the calorie burn for this same walk as 313. I realize there are differences between all of these methods: 1) only the HRM uses your own heart rate, plus your height, weight and sex; 2) the iPhone app uses height, weight, and sex, but no heart rate; and 3) I have no idea if MFP uses your height, weight, and sex or not as it is in your profile. [Would be interesting to see if others who weigh less than I do see what results they are given for the same walk and even some males. :) ]

Three measurements: 222, 313, and 765. For those of you who eat back all of your exercise calories, which number would you use? the MFP number is nearly 50% higher than the HRM and the iPhone app is over 300% higher than the HRM.

Personally, given how far out the the iPhone app is, I don't think I will be linking it with my MFP account as I don't want to publish numbers I not only believe to be outlandish, but deceiving in the overall scheme of things. Just my two cents. Thoughts???

Replies

  • toddis
    toddis Posts: 941 Member
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    Some times it's a data entry error. If the app is seriously giving you 765 calories, I'd double check the numbers. If they are correct, never use the app again =)
  • BettyBlueEyes
    BettyBlueEyes Posts: 56 Member
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    I just put in that walk to MFP, and 43 mins at 3.0mph (moderate pace, walking dog) comes out at 174 cals. I weight 162lb, am 34 (although the site thinks I'm older) - did you use the same type of walking? In which case, it does take weight into account.
  • jaz050465
    jaz050465 Posts: 3,508 Member
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    43 mins at 3mph is 158 cals for me from MFP. I'm 47 and weigh 148 pounds
  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
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    Here is a really great post in the topic. Keep in mind any method is still just an estimate, even HRM. There isnt a huge discrepancy between your HRM and MFP. Also keep in mind that heart rate isn't directly tied to calories burned. It is used by HRMs in an algorithm to help estimate calories burned along with other data points.

    http://www.myfitnesspal.com/topics/show/774337-how-to-test-hrm-for-how-accurate-calorie-burn-is?page=1

    And an explanation of how they work
    http://www.myfitnesspal.com/blog/Azdak/view/the-real-facts-about-hrms-and-calories-what-you-need-to-know-before-purchasing-an-hrm-or-using-one-21472

    As for the 700 one. Not sure where that came from but obviously incorrect.

    ETA - calories burned depend on intensity and weight.
  • xsmilexforxmex
    xsmilexforxmex Posts: 1,216 Member
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    I always trust my HRM over other methods of calculation bc it has my Height, weight, age and HR so a good estimate of my activity level.
  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
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    I always trust my HRM over other methods of calculation bc it has my Height, weight, age and HR so a good estimate of my activity level.

    The only thing relevant there is weight. Age, height, sex are not factors in calories burned. The HRM requires them for its calculations, along with heart rate as in indicator of effort in relation to VO2 max (although higher heartrate can be related to a lot more than effort ) to estimate calories with their equations.

    HRMs can be useful but they are not necessarily the most accurate.
  • Silvara_11
    Silvara_11 Posts: 133 Member
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    A very basic average is that you burn 100 calories a mile so your HRM and MFP seem to be quite close. App must have got an error.

    I have an HRM but I'm convinced it gives me too high a calorie burn so I don't make a habit of eating 100% of my burn back. However, the links shared above are very useful to test out your HRM.

    Let's face it we are constantly estimating on this site so keep things in moderation and listen to your body and hope you get the desired results!

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