Heart Rate Monitor - calorie count

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yarwell
yarwell Posts: 10,477 Member
in Health and Weight Loss
I sat here on the PC for 15 mins and told the Polar F6 I was "exercising". My heart rate averaged 41% of max with a peak of 45% of max. It says I used 23 calories.

So that's 92 calories an hour, or 2208 per day, sat using a PC. My BMR guesstimates are around 1620 so a ratio to BMR of 2208 / 1620 = 1.36 (less if sleep is taken into account at presumably a lower heart rate).

Do HRMs always include the energy you would have spent anyway sat doing nothing in their "exercise calories" ?

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  • douglasmobbs
    douglasmobbs Posts: 563 Member
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    Not too sure but curious as to what you were looking at to get that rise in heart rate.
  • mfpcopine
    mfpcopine Posts: 3,093 Member
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  • yarwell
    yarwell Posts: 10,477 Member
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    Not too sure but curious as to what you were looking at to get that rise in heart rate.
    LOL. I think that was just random wanderings in my heart rate, 41 +/- 4 is probably my sitting resting rate.
  • Di3012
    Di3012 Posts: 2,250 Member
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    I sat here on the PC for 15 mins and told the Polar F6 I was "exercising". My heart rate averaged 41% of max with a peak of 45% of max. It says I used 23 calories.

    So that's 92 calories an hour, or 2208 per day, sat using a PC. My BMR guesstimates are around 1620 so a ratio to BMR of 2208 / 1620 = 1.36 (less if sleep is taken into account at presumably a lower heart rate).

    Do HRMs always include the energy you would have spent anyway sat doing nothing in their "exercise calories" ?

    HRMs just register the calories via how fast your heart is beating.

    Quick example: I run 7 miles outside, my heartrate averaged for the whole run 160 bpm, in that session I burned 718 calories.
    Yesterday, I ran 7 miles on the treadmill, my heartrate averaged for the whole run 148bpm, in that session I burned 551 calories.

    The HRM does NOT subtract the amount of calories I would have burned during that time anyway, it just registers what I burned via my heartbeat for that time.

    Word of warning too, HRMs are notoriously inaccurate when used when a person's heartrate is less than around 90 to 100bpm.
  • bradthemedic
    bradthemedic Posts: 623 Member
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    Word of warning too, HRMs are notoriously inaccurate when used when a person's heartrate is less than around 90 to 100bpm.

    Great Protip. Thanks!
  • yarwell
    yarwell Posts: 10,477 Member
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    Word of warning too, HRMs are notoriously inaccurate when used when a person's heartrate is less than around 90 to 100bpm.
    Thanks, I had read stuff where they only recorded calories above a certain heart rate as being in "exercise mode" which fits with what you say.

    I can see how it would deceiving to add what this is telling me to MFP as "calories burned" for sure. I think I'll read the manual again, there is some stuff about "zones" I didn't take in first time.
  • tnqnt
    tnqnt Posts: 397 Member
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    The Polar Rep told me to always turn off or pause the HRM if I am under 60% of max. He said to use percent of maximum as the gauge, not bpm. At the gym, I always have between 60-80% of maximum heart rate during my workout. If it goes under, I pause it.
    I never go under, though :) lol

    EDIT: This is for fat loss. I do go over 60-80 % for fitness but when focusing on fat loss, I should be under 80, and he said to cycle between 60 and 80, don't stay constant.... :)
  • tnqnt
    tnqnt Posts: 397 Member
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    I can see how it would deceiving to add what this is telling me to MFP as "calories burned" for sure. I think I'll read the manual again, there is some stuff about "zones" I didn't take in first time.

    The zones are the fat burn zone, the fitness improving zone and the maximum performance zone..


    See this:

    http://www.polar.fi/en/training_with_polar/training_articles/maximize_performance/running/polar_sport_zones_for_running
  • kitinboots
    kitinboots Posts: 589 Member
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    I worked out I would burn about 58 calories an hour doing nothing, so I deduct this from my HRM's calories burned estimate.
    If it says I burned 367 calories in 30 minutes of running, I record 337.
  • willismack2
    willismack2 Posts: 84
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    I worked out I would burn about 58 calories an hour doing nothing, so I deduct this from my HRM's calories burned estimate.
    If it says I burned 367 calories in 30 minutes of running, I record 337.

    I do this also. I subtract 70 calories/hr from the exercise total
  • yarwell
    yarwell Posts: 10,477 Member
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    Seems I can define a heart rate zone for exercise and it will tell me the time spent in that zone as well as the total. Subtracting a base load seems a sensible approach.
  • kyle4jem
    kyle4jem Posts: 1,400 Member
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    Do HRMs always include the energy you would have spent anyway sat doing nothing in their "exercise calories" ?
    Yes!

    I've worn my HRM (Polar FT4) for three hours while I was working (i.e. sitting at my lap top, getting up and going to the bathroom, going up and down stairs for drinks etc) on a number of occasions. I've also worn it going into work on the train when I've been sat motionless, half-asleep, and I've been able to calculate my true BMR and AMR from these readings and thus my AMR/min.

    After I've exercised, I subtract my AMR from any HRM readings and/or MFP values.

    Now, given that HRMs calculate calories burnt based on heart rate readings, it could be that these readings are less accurate when not actually increasing your heart rate through exercise, and perhaps the AMR deficit is technically negligible, but I'm anal enough to want to do all the maths anyhow :happy:

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