HRM vs fitbit and phone app - burnt cals

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Cazzyxo
Cazzyxo Posts: 104 Member
in Fitness and Exercise
Hey,

Iv just got a new polar ft40 HRM. I just did a 30min run. My running app and fitbit said around 300kcals, howevee my HRM said 500kcals! Quite a big difference. I did accidently stop and start my HRM 10mins in as the max heart rate alarm was sounding but i immediately restarted it? Which should i go by? :)

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  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
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    You will inevitably get answers that say HRMs are most accurate however this is not always the case, even for steady state cardio, as much as 20% off.

    Here is some info on what can affect accuracy
    http://www.myfitnesspal.com/topics/show/773451-is-my-hrm-giving-me-incorrect-calorie-burn

    If you scroll down there is a link to a spread sheet that gives steps for settin it up for a more accurate burn.

    On average, running burns around 100 calories per mile, a little less for lighter people. Your profile pic doesn't look like you weight enough to put you over the average.

    I'd go with the lowest value, then again, I always do.
  • jacksonpt
    jacksonpt Posts: 10,413 Member
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    You will inevitably get answers that say HRMs are most accurate however this is not always the case, even for steady state cardio, as much as 20% off.

    Agreed.

    10cals per minute is usually a good starting point for people in decent shape (which you appear to be).
  • Cazzyxo
    Cazzyxo Posts: 104 Member
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    Thanks! So confusing, wanted a HRM for more accuracy but left wondering if it is worth it at all :/
  • jacksonpt
    jacksonpt Posts: 10,413 Member
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    Thanks! So confusing, wanted a HRM for more accuracy but left wondering if it is worth it at all :/

    while I don't automatically subscribe to the "HRMs are more accurate" mantra, I do believe that they are more consistent. i.e. if it's off by 10%, it'll be off by about that same 10% most of the time. I'm not sure I'd say the same thing for other methods of estimating calorie burns.

    What's that mean? It means that after you use an HRM for a month or so, it should (emphasis on should) be easier to tweak based on how your expected results line up with your actual results.
  • Cazzyxo
    Cazzyxo Posts: 104 Member
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    Thanks.

    Slightly off topic but i did a fitness test on the ft40 and its got my max heart rate at 170. Iv ran today and done a dvd, my heart rate was 180-190, not sure if this is gonna be making the burn look higher than it is?!
  • jacksonpt
    jacksonpt Posts: 10,413 Member
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    It very well may. Getting your max HR set reasonably close is one of the first things you should do wtih a new HRM. IMO, set it to 10% higher than whatever it thinks your max HR is.
  • BrianSharpe
    BrianSharpe Posts: 9,248 Member
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    Hey,

    Iv just got a new polar ft40 HRM. I just did a 30min run. My running app and fitbit said around 300kcals, howevee my HRM said 500kcals! Quite a big difference. I did accidently stop and start my HRM 10mins in as the max heart rate alarm was sounding but i immediately restarted it? Which should i go by? :)

    How far did you run?

    Runners World suggests the following formula to sanity check your net caloric expenditure running:

    .63 x your body weight in lbs x distance in miles (for gross calories use .75)

    http://www.runnersworld.com/weight-loss/how-many-calories-are-you-really-burning?page=single
  • Cazzyxo
    Cazzyxo Posts: 104 Member
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    I ran for 30mins and 5mins warm up walk and cool down. On last week of C25K.

    I dont know how to mannually change my max heart rate cus im guessing thats what the problem is...
  • jacksonpt
    jacksonpt Posts: 10,413 Member
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    30 minutes and 300 cals is 10 cals per minute - pretty reasonable for most people.

    30 minutes and 500 cals is 16.7 cals per minute - REALLY high for the average person. Few people can sustain that type of burn for a few minutes, never mind a half hour.
  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
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    I ran for 30mins and 5mins warm up walk and cool down. On last week of C25K.

    I dont know how to mannually change my max heart rate cus im guessing thats what the problem is...

    If you go to the link I posted above, about incorrect calories, and scroll down, Heybales posted another link that takes you to a spreadsheet that walks you through the steps of setting up for more accurate heart rate zone.
    I can't link it right now, on my phone.
  • hopefaithlove24
    hopefaithlove24 Posts: 454 Member
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    I ran for 30mins and 5mins warm up walk and cool down. On last week of C25K.

    I dont know how to mannually change my max heart rate cus im guessing thats what the problem is...

    Read the instructions, I got an FT4 yesterday and everything you need to know is in the instructions:)
  • Cazzyxo
    Cazzyxo Posts: 104 Member
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    Thanks for all your help. Managed to set my max heart rate higher as was at 178 and most the time i was running it was top 180s early 190s..

    Ran again today 30mins and burn was 433. Still confused at which reading i should listen to!
  • Azdak
    Azdak Posts: 8,281 Member
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    Was that 178 the top of a heart rate zone or was it you Maximum Heart Rate?

    178 sounds low for a 22 year old--by that I mean I am surprised the HRM would default you to that number.

    At your weight, running a 10:00 min/mile pace would put you at roughly 590-600 calories per hour. Running a 9 min mile would put you at about 660 per hour.
  • Cazzyxo
    Cazzyxo Posts: 104 Member
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    178 was just given to me by the HRM after a fitness test. I manually set it to 195bpm as this is around what i hit when im running. Still giving me a high burn tho :/

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