Confused about HRM calorie burn

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penroseg
penroseg Posts: 53 Member
in Fitness and Exercise
I got my heart rate monitor about 2 months ago. It's a nice one by Polar with a chest strap. As soon as I got it, I set it up, entered my personal info (height, weight, age, etc.), and have been using it. Yesterday morning, I ran a 2.5 mile loop, and I wrote down my time, avg heart rate, and calories burned. This morning I realized that I haven't adjusted my weight in my HRM since I got it, and I've lost 12 lbs since I first programmed it. So I changed it to my current weight. After that, I ran the same 2.5 mile loop. I went to write down my info. My time was about the same, so was my avg heart rate, but my calories burned was way higher! By over 100 calories!!!

Could someone explain how my heart rate monitor thinks that I burned more calories at a lower weight (12 lbs less) doing the exact same thing? I would have thought it would have been the other way around, or much closer in numbers.

Thanks!!! :happy:

Replies

  • AmyRhubarb
    AmyRhubarb Posts: 6,890 Member
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    I don't have a polar, but my New Balance gave me high and low readings at odd times all of a sudden - I changed the battery in the chest strap and that took care of it. Not sure what to tell you about the higher calorie burn after adjusting your weight, but that might be a battery issue too? Maybe try a fresh battery & see if that helps.

    Good luck! And congrats on the weight loss!
  • penroseg
    penroseg Posts: 53 Member
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    Anyone?
  • scorpio516
    scorpio516 Posts: 955 Member
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    Here is what the HRM should be doing:

    ((-20.4022 + (0.4472 x HR) - (0.1263 x W) + (0.074 x A))/4.184) x 60 x T

    HR is average HR, A is age in years, W is mass in kg, T is time in hours.
    Note: this equation is for women, men have a different equation.

    Do the math and compare to your HRM, from both activities (using the false weight). That'll get you headed in the right direction.
  • larkiedeek
    larkiedeek Posts: 203 Member
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    did you change anything else when you re-set your weight?

    I would go back through and check what is set. If you have set it all for how you are now I would go with that.

    They are not 100% accurate anyway.


    Just ordered an FT7 after my old HRM broke this week so it will be interesting to see how it differs.
  • penroseg
    penroseg Posts: 53 Member
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    Nope. The only thing I changed was my weight. I lowered it by 12 lbs. That's it. So weird. Also, my HRM is only about 8 weeks old.
  • firedragon064
    firedragon064 Posts: 1,090 Member
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    How about the heart rate? Maybe this time your heart rate went up?
    Also your V02 Max, your watch calculate it for you or you have to enter manual/
  • penroseg
    penroseg Posts: 53 Member
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    My heart rate was very similar. My average beats per minute was almost identical, and I ran the same distance in about the same time. The VO2 is calculated by the watch. Makes no sense.... :noway:

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