Polar FT4 - calories are too high?

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So I used to have a Garmin Forerunner 410 with a HRM. I used it religiously for a good few years, it got me through training for 3 half marathons and I always used it in the gym as a HRM. The calories always seemed accurate to me.
I'm not planning on running much anymore so I sold it and have got a polar ft4 instead. Tonight I did body pump and always on my Garmin id be around 210-230 (depending on the body pump release) but tonight my polar ft4 says 339! That's way over what my Garmin said.
I understand the Garmin is very good and learns your fitness over time etc. does the polar do this? Do I need to do something to it to learn my fitness?
I worry because I don't seem to fit into the basic Max HRM calculation of 220-age or what ever it is, I always have a high heart rate when running for example but I can hold a conversation and keep that level for miles. So I'm not sure what to believe now!

Replies

  • MeanderingMammal
    MeanderingMammal Posts: 7,866 Member
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    Garmin and Polar use different algorithms for their calorie estimations, you've gone from a reasonable device to an entry level consumer grade device that doesn't allow you to give it any meaningful information to refine the approximations.

    Your Garmin would have been overestimating already, so I'd suggest just taking half of what the Polar says as an approximation.
  • BusyRaeNOTBusty
    BusyRaeNOTBusty Posts: 7,166 Member
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    I've run into this problem in reverse. I used to use a Polar FT4 exclusively. I ate based on that and never ran into any problems (like unexpected gains). But now I have a Garmin 500 with a HR strap. Garmin's readings are much lower. So yeah, I don't know.
  • GemmaC25
    GemmaC25 Posts: 3
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    To be honest I'd be very surprised if my Garmin was over estimating. I burned 240-270 calories on a 3 mile run (Polar reckons 311!) - I can't see my 'actual' calorie burn being any less than 240?

    Anyway, I'm logging what the polar says now, even though I feel it's too much!
  • MeanderingMammal
    MeanderingMammal Posts: 7,866 Member
    edited March 2015
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    GemmaC25 wrote: »
    To be honest I'd be very surprised if my Garmin was over estimating.

    For running, it would have been fine. For something like bodypump, the subject of the question, it would have been overestimating. Your Polar will be significantly overestimating.

    They're an aid, and shouldn't trump a dose of common sense.
  • BrianSharpe
    BrianSharpe Posts: 9,248 Member
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    Most HRMs aren't terribly accurate for anything other than steady state cardio and even then there is a great deal of variability. While this may be a little OT here's an interesting article on DCRainmaker's site re: Garmin algorithms

    dcrainmaker.com/2010/11/how-calorie-measurement-works-on-garmin.html

    For sanity checking calorie burns for running try multiplying .63 x weight (in lbs) x distance (in miles)
  • rudy336
    rudy336 Posts: 66 Member
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    ive used the polar Ft4 for almost a year now. i find that for me anywhere from 151-160 bpm is where i burn the most calories. i have used this for several workouts, gym with weights, and lots of cardio, elleptical and walking. never had a problem. lost 25 pounds or so. :) i love my ft4
  • brianpperkins
    brianpperkins Posts: 6,124 Member
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    Another thing to consider is if the device reports gross or net calories.
  • AmazonMayan
    AmazonMayan Posts: 1,168 Member
    edited April 2015
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    I use Ft4 and if a burn ever seems a little high, I check it against several sites (I Google for burn calculators) and the Ft4 usually shows much lower than the sites for me. Hiking is the one that EVERY site says much higher than the polar. I only keep it running when I am moving too and we don't go slow nor do easy trails and my heart rate stays up.

    Sometimes I eat all the calories (within reason) if I know it was a strenuous workout and sometimes I adjust the number lower when logging. For the record, I can't eat all the hiking calories lol they just get banked. It's only every couple weeks anyway.

    I really don't get many ridiculous readings and I'm still very overweight so..... I have really low blood pressure so I often wonder if that makes it underestimate it for me. Even before adding exercise and at my heaviest and I'm 47 years old, my blood pressure was only up to what is considered normal for a healthy person. ::::shrugs:::: I'm losing and at least the HRM lets me know if I need to push harder as my fitness improves. I love my Ft4.