Timex HRM Calories Burned Accuracy

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BobSassafrass
BobSassafrass Posts: 85 Member
in Fitness and Exercise
I recently purchased a chest strap HRM. From what I've read these are great for aerobic exercise but not so great at calculating calories burned for targeted exercise. In that vein I've used it for jogging and P90X cardio. But the numbers seem extremely high. For 50 minutes of P90X cardio it showed 850 calories burned and 30 min of jogging over 600. While MFP estimates are about half that. So which one should I trust?

My stats: barely above novice level fitness, ~200 lbs, 5' 10", average heart rate for P90X cardio ~160bpm.

Also I do get similar numbers to the HRM via this website http://www.shapesense.com/fitness-exercise/calculators/net-versus-gross-calorie-burn-conversion-calculator.aspx

Replies

  • jasonheyd
    jasonheyd Posts: 524 Member
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    I had a Timex HRM and switched to a Polar H7, which I pair to the Digifit or the Polar apps on my iPhone. I always found the Timex calorie burn estimates to be high.

    I always use the Compendium of Physical Activity as a baseline for my estimates and, for your height & weight, the Compendium estimates a 642 calorie/hour burn for jogging. That's only a baseline for research purposes, so I'd expect one hour to get somewhere above 642 calories (taking your "novice level fitness" into account), which means 30 minutes would be about half that.

    SO... No, personally, don't think the Timex results are very accurate. :)

    Edit: In other words, I'd go with MFP on this one. :)
  • jasonheyd
    jasonheyd Posts: 524 Member
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    By the way, if you want to play around with the Compendium, I've posted a Google Docs spreadsheet that you can copy for yourself:

    https://docs.google.com/spreadsheet/ccc?key=0Al5RZKHzjd6wdG5pTWVVNXV6MnZMZVVlQUNSenFDWkE

    You'll need a Google account to copy/use it.
  • BobSassafrass
    BobSassafrass Posts: 85 Member
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    Great response, thanks so much!
  • lovza_flirt
    lovza_flirt Posts: 14 Member
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    I had a timex hrm and it broke so I bought polar 4. I found that the timex estimate was way higher then the polar. I feel my polar is more accurate, and I find I'm actually closer to or under the calories the cardio machines say at the gym.
  • Mokey41
    Mokey41 Posts: 5,769 Member
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    Timex HRM's have a reputation for being inaccurate on the high side.

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