Accuracy of Heart Rate Monitors

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bull_dog44
bull_dog44 Posts: 16
in Health and Weight Loss
Hey Everyone,

Any idea how accurate a heart rate monitor is at calculating calories burned? I bought a Polar Heart Rate Monitor (chest strap and all) and it shows me that with an average heart rate of 130 BPM, from walking around all day, I burn roughly 4000 calories in 7 hours. This seems really high to me...does anybody have any thoughts?

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  • HartJames
    HartJames Posts: 789 Member
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    They aren't meant to be worn for anything but cardio.....
  • musicgirl99
    musicgirl99 Posts: 252 Member
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    Did you calibrate it before you put it on? Those numbers don't sound right. Maybe you didn't set it up with your age, height, weight, etc.??
  • smorealloyquik9
    smorealloyquik9 Posts: 10 Member
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    Maybe you're more interested in an all day calorie calculator like a FitBit? Unless those 7 hours were a workout for you. I used my Polar for strength training and cardio workouts, and I find that it's pretty accurate, as long as I keep my weight and age updated.
  • therealangd
    therealangd Posts: 1,861 Member
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    If you maintained an average heart rate for 7 hours of 130 bpm, then yes, you probably burned 4000 calories. If you're resting heart rate is in the vicinity of 60-70.

    However, to maintain an average heart rate of 130 bpm for 7 hours, you would probably have to be walking a fairly fast pace. We're talking walking a marathon in 7 hours pace. It's not a leisurely pace. I doubt you'd be doing that at work.


    This is the formula to calculate calories burned based on average heart rate, weight and age.

    (-20.4022 + 0.4472 x HR - 0.1263 x weight + 0.074 x age) / 4.184
  • bull_dog44
    bull_dog44 Posts: 16
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    Yeah, I had it set to my age/weight....my resting heart rate has always been a little high. About 80.

    I didn't find it particularly taxing, I was just walking around, moving boxes, etc.
  • bull_dog44
    bull_dog44 Posts: 16
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    Isn't everything technically cardio though? I mean, as long as you're up and moving around.
  • mcarter99
    mcarter99 Posts: 1,666 Member
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    For most fit people (not obese), we can't burn more than about 10 calories/minute at cardio. So if I did high HR cardio for 7 hours, I'd burn about 4200 calories. I couldn't do that for anywhere near that length of time. So it sounds highly suspect to me.

    Where do you work? There are things that cause interference like high voltage lines. Also weak batteries in either part can cause bad readings.

    Can you take a manual HR reading while at work, while it's saying 135ish, and see if it's correct? Count your pulse with your fingers for 10 seconds then multiply that by 6.

    Do you generally eat over 4000 calories a day to maintain, or is weight flying off you?

    This is the section from a Polar HRM manual that talks about possible causes of weird HR readings.

    http://www.polarusa.com/us-en/support/FAQs/Abnormal_Heart_Rate_Readings_During_Exercise?product_id=22998&category=faqs
  • bull_dog44
    bull_dog44 Posts: 16
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    I'm a Project Manager and I specialize with working with School DIstricts....so I tend to be around a lot of WiFi signals if that causes anything.

    The BPM does match up across multiple HR's and the manual method.

    I definitely binge eat...if I eat a regular diet with 1500-2000 calories a day and workout for a week it's not uncommon for me to lose 10-12 pounds. But I put it on during a few days off where I eat everything in sight (generally out of boredlom or just the fact that it sounds good). It's not a shock for me to follow up one great week with a week of eating 5000 calories a day and being completely sedentary.
  • vixsummer
    vixsummer Posts: 10 Member
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    Maybe you're more interested in an all day calorie calculator like a FitBit? Unless those 7 hours were a workout for you. I used my Polar for strength training and cardio workouts, and I find that it's pretty accurate, as long as I keep my weight and age updated.

    What's a FitBit? I'm working at a summer camp and will be playing sports and walking a lot, so I wanted to find out if I burned anything during my days as well. Maybe this would work for me too.
  • Di3012
    Di3012 Posts: 2,250 Member
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    Hey Everyone,

    Any idea how accurate a heart rate monitor is at calculating calories burned? I bought a Polar Heart Rate Monitor (chest strap and all) and it shows me that with an average heart rate of 130 BPM, from walking around all day, I burn roughly 4000 calories in 7 hours. This seems really high to me...does anybody have any thoughts?

    Yes, if you wear a HRM in that fashion, the calories it displays will be totally inaccurate, as it was not designed for anything other than cardio.

    For all day wear you need a fitbit from what I have gathered.
  • Di3012
    Di3012 Posts: 2,250 Member
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    Isn't everything technically cardio though? I mean, as long as you're up and moving around.

    No, it isn't. If it were, those that are morbidly obese (but still move about) would have plenty of cardio up their sleeve, but they do not.

    According to the American College of Sports Medicine, cardio, or cardiovascular exercise, is any activity that increases heart rate and respiration while using large muscle groups repetitively and rhythmically. - excerpt taken from the site below.

    Read more: http://www.livestrong.com/article/114986-definition-cardio-exercise/#ixzz1yKyySl6Z
  • secretlobster
    secretlobster Posts: 3,566 Member
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    I agree that the HRM is only really meant for purely cardio activities. A fitbit is not a bad investment if you're really interested in calories burned over the course of a day. But yes 4000 calories in 7 hours is nearly impossible.
  • tigersword
    tigersword Posts: 8,059 Member
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    Isn't everything technically cardio though? I mean, as long as you're up and moving around.

    A heart rate monitor like a Polar is only designed to track steady state cardio activity. Jogging, cycling, etc. it's completely inaccurate for all day wear, or anaerobic activity (sprinting, strength training.) even when used for its designed purpose it's only about 85-90% accurate, when you try to use it for anything else, it's pretty much useless.
  • Martucha123
    Martucha123 Posts: 1,093 Member
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    Isn't everything technically cardio though? I mean, as long as you're up and moving around.

    if you were walking all day all the time then yes, you can count is as cardio
    but if you walk / stand / sit, then no...

    HRM is accurate only for cardio (ideally not intervals but same intensity all the way cardio)

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