Setup Polar HRM for more accurate calorie burn for known BMR

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  • schmoozie26
    schmoozie26 Posts: 63 Member
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    bump
  • ArchyJill
    ArchyJill Posts: 548 Member
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    I hate math, but I hate inaccurate calorie burn estimates even more. Thanks for figuring this out!!
  • twkelly
    twkelly Posts: 91 Member
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    bump
  • heybales
    heybales Posts: 18,842 Member
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    Honest question. How much of a calorie difference are we talking here? Hundreds of calories burned per workout?

    Very interesting question. The study in the OP link showed women potentially up to 33% off on estimated calorie burn, just based on MHR and VO2max defaults being used over true MHR/VO2max. And those are the bigger effectors of calorie burn estimate. But those are included in the calc along with the BMR, so they all have potential.

    Women vary all over the place, probably because they are tougher than men, and willing to push their body to extremes. Obviously childbirth as an example of something a man could never handle!

    As to just the BMR difference by itself.
    So one example below, or above, or wherever it went now, 13 yrs old if LBM BMR used, 51 real age for height/weight BMR, and 94 yr old if netting below BMR forcing it to that level. So that example showed the addition of netting a mere 400 or so more calories could have this range effect.

    So lets say 1 hr workout at medium intensity.
    23.4% BF, LBM of avg 13 yr old at same height/weight - 403.
    avg LBM of age/height/weight - 359.
    lowered BMR of 94 yr old same height/weight - 309.

    So true, only about 50 cal difference between what watch was guessing, and worst case, or best case, scenario.

    For those wondering about how I got those estimates of calorie burns, BMR/24*7, common estimate for jogging slow. Your intensity may vary, just needed a comparison point.
  • rmk20togo
    rmk20togo Posts: 353 Member
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    Also, if you want MFP setup to just do that automatically, like lower the daily goal as weight goes down, do the following setup.
    Settings - Diet/Fitness profile
    Activity Level - Lightly Active
    Weight loss goal - 1 lb weekly

    That should set your goal to about 1680 daily net. And then with more accurate calorie estimates of your favorite avg 13 yr old - you'll keep that muscle and make it stronger.

    Side comment, it's impossible for the body to build muscle with suppressed metabolism. After the exercise takes from the calories you eat, if the rest is below your real potential BMR, the body has to decide how it slows down to take care of functions the BMR does. Building muscle is not one of them.

    But eating higher, it is possible, though very difficult. But after 5lb drop, remeasure and see if you have gotten younger yet. And don't be upset if you got older, which is possible.

    With this criteria, MFP puts me at 1360 so I did a custom set at 1430 and will adjust when (or if) the weight goes down). I'll NET here for a week and then increase to 1600+. Once I increase NET, then I tell my HRM I'm 13?

    Your "side comment" explains why I've worked so hard 6x/week for 4 years and haven't seen any real muscle definition.

    Sorry to be so dense. This is all so interesting to me, but I just can't get my mind around it.

    Edit Note: 1430 is gonna suck on rest days!
  • easfahl
    easfahl Posts: 567 Member
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    Thanks so much OP, this is great info.

    Here's a practical example, as I did the hydrostatic body fat % test last in the past 60 days, done by two different facilities in my college-based hometown.

    I'm an athletic 5'4" tall, 33 year old female who weighs 142 lb. I currently have MFP set so that my NET is 1550 per day. My BF% tested via hydrostatic testing is 23.6%. I've never trusted the military ones, or even the pulse impedence ones, as I'm a broad-shouldered, quite stalky 5'4" female. They're usually absurbly all over the place, usually obviously high.

    The OP's Polar age correction method has my true (via the website he mentioned) BMR based on my true BF% at 1437 per day. Since I've been NETting 1550 I'll use the first set of instructions. Now, I remove my BF% and adjust the age until it shows the closest value to 1437, which is 28 years old. So I'll adjust the age of my Polar FT7 to 28. This makes a lot of sense to me.

    NOTE: PLEASE READ THIS PART!!!! I will warn people about BF% testing anything other than hydrostatic, Bodpod, etc. Even calculators/estimators that take multiple measurements into account are, at best, ESTIMATES!

    Example: my true BF% is 23.6%, tested hydrostatically by two different facilities. The OP's suggested website BF% estimate calculator has me at Navy (men/women) = 28.6%, Navy (women) = 26.6%, Covert = 28.3%, and my Tanita electrical pulse impedence usually states around 31%.
  • glittermouse
    glittermouse Posts: 590 Member
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    Awesome. Have a Polar FT7 on the way. Should have it next week. Gonna look into this so I can get it set up correctly right from the get go.
  • rmk20togo
    rmk20togo Posts: 353 Member
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    Example: my true BF% is 23.6%, tested hydrostatically by two different facilities. The OP's suggested website BF% estimate calculator has me at Navy (men/women) = 28.6%, Navy (women) = 26.6%, Covert = 28.3%, and my Tanita electrical pulse impedence usually states around 31%.

    I'm glad I'm not the only one all over the body fat place. My BF scale=32%, Navy (women)=28.7%, Covert = 23.25%, I live in a town with 4 universities (including Vanderbilt) and not one has hydrostatic testing.
  • heybales
    heybales Posts: 18,842 Member
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    If I have been netting around 1500-1600 on average.... my wt entered into HRM should be around 170...Which I ironically is my goal weight.

    But once constantly netting above 1880-BMR and no wt change.. I change it to my current wt and age to 33 yrs old.(4 yrs younger)

    How long should I stay above BMR with my net before I reassess?
    a month?

    You are correct if changing the weight lowers it better than upping the age. Older doesn't drop it as much. But I thought a much more interesting effect to see what age you would be with a suppressed metabolism.

    And true, if you can net at the higher BMR that body composition gives you, even better, and younger in that sense.
    One week, you don't have much change to effect.
  • heybales
    heybales Posts: 18,842 Member
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    With this criteria, MFP puts me at 1360 so I did a custom set at 1430 and will adjust when (or if) the weight goes down). I'll NET here for a week and then increase to 1600+. Once I increase NET, then I tell my HRM I'm 13?

    Your "side comment" explains why I've worked so hard 6x/week for 4 years and haven't seen any real muscle definition.

    Sorry to be so dense. This is all so interesting to me, but I just can't get my mind around it.

    Edit Note: 1430 is gonna suck on rest days!

    Crap, sorry, that was a mix of manual tweaks, or forgetting to add /2.
    Yours was 1/2 lb weight loss weekly, making it 1613.
    True weight loss would be more than that, that was just the settings to get closest to potential true BMR as end result.
  • kayl3igh88
    kayl3igh88 Posts: 428 Member
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    bump for later
  • heybales
    heybales Posts: 18,842 Member
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    NOTE: PLEASE READ THIS PART!!!! I will warn people about BF% testing anything other than hydrostatic, Bodpod, etc. Even calculators/estimators that take multiple measurements into account are, at best, ESTIMATES!

    Example: my true BF% is 23.6%, tested hydrostatically by two different facilities. The OP's suggested website BF% estimate calculator has me at Navy (men/women) = 28.6%, Navy (women) = 26.6%, Covert = 28.3%, and my Tanita electrical pulse impedence usually states around 31%.

    Very true. At least if the estimate can be consistent you can discern direction. The impedance method to me as the most potential for differences, being so reliant on hydration level. Measurements you gotta be careful not to do it after doing weight lifting the day before, no retained water in muscles. But if body type isn't too bad, decent.

    At least with the concept of it's use in calculating BMR, that range of 23.6 to 31% means the difference between 1605 to 1485, only 120. Which isn't great, 5% difference would be better. Which on yours, all 3 estimates hit that, only the scale is an outlier, and your true one is too.

    Bodypod's should start coming down in price for more places to get them, and rates hopefully decent enough.
  • boggsmeister
    boggsmeister Posts: 292 Member
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    Bumping for later
  • KellyBurton1
    KellyBurton1 Posts: 529 Member
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    wow, alot of info. Need to bump to clear my head!
  • janjan369
    janjan369 Posts: 98 Member
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    bump as I just got my PolarFT4
  • annarouni
    annarouni Posts: 127 Member
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    Really appreciate the thorough explanation! Got a Polar but haven't quite got it figured out yet so that I make the most of it. This should help a lot. :flowerforyou:
  • Justacoffeenut
    Justacoffeenut Posts: 3,808 Member
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    bump
  • healthbunny
    healthbunny Posts: 86
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    Bump for later
  • terri0527
    terri0527 Posts: 678 Member
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    Bump
  • C00lCountry
    C00lCountry Posts: 282
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    Interesting!

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