Should I trust a HRM for calories burned?

kensgirl2
kensgirl2 Posts: 21 Member
in Health and Weight Loss
I have a digital heart rate monitor set with my stats. My question is, should I trust what it tells me for calories burned? It seems to be quite a bit more than what fitburn tells me for a particular exercise, which to be honest I thought was more than what I was really burning in the first place! Can these monitors be trusted to give a somewhat accurate count?

Thanks!

Replies

  • HIITMe
    HIITMe Posts: 921 Member
    I have a digital heart rate monitor set with my stats. My question is, should I trust what it tells me for calories burned? It seems to be quite a bit more than what fitburn tells me for a particular exercise, which to be honest I thought was more than what I was really burning in the first place! Can these monitors be trusted to give a somewhat accurate count?

    Thanks!

    if they cant be trusted, you wasted your money purchasing one
  • dg09
    dg09 Posts: 754
    Hasn't failed me yet. What brand is it?
  • EdTheGinge
    EdTheGinge Posts: 1,616 Member
    I've never used a fitbit but have recently got a HRM at I'd say it was more accurate as it'll take it based on how much effort/strain there is on your heart, I could be completely wrong.
  • kensgirl2
    kensgirl2 Posts: 21 Member
    It's a Timex one that I bought a few years ago that I just dusted off recently. Better late than never, right?
  • kensgirl2
    kensgirl2 Posts: 21 Member
    I have a digital heart rate monitor set with my stats. My question is, should I trust what it tells me for calories burned? It seems to be quite a bit more than what fitburn tells me for a particular exercise, which to be honest I thought was more than what I was really burning in the first place! Can these monitors be trusted to give a somewhat accurate count?

    Thanks!

    if they cant be trusted, you wasted your money purchasing one

    Uh, thanks.
  • mmapags
    mmapags Posts: 8,934 Member
    There is no easy answer to this. What kind of HRM is it? Is it set up correctly for you? HRMs are generally a fairly accurate estimate if you bought a quality one and it's set up correctly but it is still just an estimate based on formulas. Also, it depends on what kind of exercise you are estimating. They are most accurate for moderate to high intensity steady state cardio as that is what thier algorythims are designed for. They overestimate low intensity steady state cardio and are useless for strength training.

    Personally, I never use more than 70% of what my my HRM tells me as a burn. I may be conservative but I'd rather underestimate by 100 calories than over estimate by that amount.
  • mmapags
    mmapags Posts: 8,934 Member
    It's a Timex one that I bought a few years ago that I just dusted off recently. Better late than never, right?

    I also have a Timex. They have a reputation of overestimating slightly.
  • kaypat09
    kaypat09 Posts: 130 Member
    I had a Timex HRM before I bought my Polar, and it was overestimating my calories by almost 50% in some cases. I'd say just be cautious. If you're going to eat back your exercise calories, maybe eat back half of them?
  • tropaze
    tropaze Posts: 317 Member
    My question is does it have a chest strap? I had one that was only the wristwatch and it was slightly higher since it only took the HR when I touched the sensor, my new one with the chest strap is more accurate and I go by what it says.
  • jacksonpt
    jacksonpt Posts: 10,413 Member
    It's just another estimate. As are all the other calorie burn numbers you'll come across.

    Which you choose to use doesn't much matter. Pick one and be consistent with it for a month. Then evaluate your results.

    If your logging has you in a deficit but you are gaining, then chances are your estimates are off (eating more than you think and/or burning less than you think). If your logging has you in a surplus but you are losing, then chances are your estimates are off (eating less than you think and/or burning more than you think). Tweak as necessary.
  • pander101
    pander101 Posts: 677 Member
    I use one and found it to be a little more accurate than using MFP's calculations. I have a Polar F4. I had a different brand before and still found my older one a little more accurate than the site. Personally, I think you should trust the HRM.
  • BeLightYear
    BeLightYear Posts: 1,450 Member
    I had a Timex HRM before I bought my Polar, and it was overestimating my calories by almost 50% in some cases.

    Me too, Timex HRM is bad news.....
  • sladey182
    sladey182 Posts: 1
    I use the MiCoach HRM and it shows considerably less than what MyFitnessPal tells me....I would say the HRM is more accurate!
  • johnwhitent
    johnwhitent Posts: 648 Member
    It's a Timex one that I bought a few years ago that I just dusted off recently. Better late than never, right?

    I also have a Timex. They have a reputation of overestimating slightly.

    I agree that the Timex hrm's seem to overestimate the calorie burn, but I still love my Timex Run Trainer! dcrainmaker.com has some great info on hrm calorie estimates and a ton of great reviews on hrm's and other stuff, from the perspective of a triathlete who has played with about every hrm out there. It's very detailed stuff but great info.
  • kensgirl2
    kensgirl2 Posts: 21 Member
    Yes, it has a chest strap with it. I figured it has to be more accurate than what a general website is going to tell me since it measures MY heart rate and not just use a "standard" rate.

    Thanks for all the replies! I really appreciate it!! :happy:
  • Zombielicious
    Zombielicious Posts: 246 Member
    I used to have a Timex and from my experience, and from other reviews I've seen, they way overestimate calories. I bought a Polar F7 not too long ago...probably one of my better investments. Based on research, Polar are probably closer to your actual calories burned than most other HRM brands.
  • mercymarque
    mercymarque Posts: 450
    i have the Poar FT4 and I love it. I find that the machines at the gym and mfp over estimate the amount of calories burned. I trust my HRM.
  • vorgas
    vorgas Posts: 741 Member
    If you are this concerned about accurate calories burned through exercise, then you need to know your VO2 Max (which is the amount of oxygen you can process). Higher VO2 Max means a lower heart rate at a given intensity.

    That being said, if you're going this close you're probably doing it wrong :) High performance athletes, body builders, etc may have concerns, but you should be within a couple hundred calories.

    Here's how to determine your VO2 Max and how to use it to determine the calories burned.
    Determine VO2 Max: http://www.shapesense.com/fitness-exercise/calculators/vo2max-calculator.aspx
    Calculate Calories: http://www.shapesense.com/fitness-exercise/calculators/heart-rate-based-calorie-burn-calculator.aspx
  • XXXMinnieXXX
    XXXMinnieXXX Posts: 3,459 Member
    I now have a body media / ki fit and that comes out higher than the HRM. The fitbit came out WAY too low! I have a friend where it's almost perfect though! I'd trust the HRM over the fitbit for sure as it's detecting your heart rate!
  • 78brownie_wechanged
    78brownie_wechanged Posts: 291
    I had the Ironman as my first HRM. It was very inaccurate. Not sure if it was my model or not but I returned it and purchased a Polar. No problems.
    It's a Timex one that I bought a few years ago that I just dusted off recently. Better late than never, right?
  • DebbieLyn63
    DebbieLyn63 Posts: 2,654 Member
    I have heard that Timex can greatly overstate calorie burns, especially for women. I have a PolarFT4 and it gives me half the number that my bike computer, and MFP says. Even with the lower number, I find that if I eat back my calories burned, it puts me into maintenance or even gain level.
    In theory, it shouldn't be the case, but in real life for me, that is my experience. So I exercise for cardio and strength, but eat at a calorie deficit for losing weight.

    And I don't need a bunch of people telling me that I am wrong on this. I am only saying what I have found to be true for ME over the past 5 months.
  • DebbieLyn63
    DebbieLyn63 Posts: 2,654 Member
    If you are this concerned about accurate calories burned through exercise, then you need to know your VO2 Max (which is the amount of oxygen you can process). Higher VO2 Max means a lower heart rate at a given intensity.

    That being said, if you're going this close you're probably doing it wrong :) High performance athletes, body builders, etc may have concerns, but you should be within a couple hundred calories.

    Here's how to determine your VO2 Max and how to use it to determine the calories burned.
    Determine VO2 Max: http://www.shapesense.com/fitness-exercise/calculators/vo2max-calculator.aspx
    Calculate Calories: http://www.shapesense.com/fitness-exercise/calculators/heart-rate-based-calorie-burn-calculator.aspx

    The VO2 info made my eyes glaze over and was a bit confusing. However, the heart rate calculator was really eye-opening!

    Looking back in my exercise diary notes I found a day back in November when I first got my HRM where I rode my bike for 1 hour and my Ave HR was 114
    According to my HRM I burned 394 calories in that hour.
    According to the calculator from that site you suggested-
    It gave me 329 gross calories for a 60 min workout at an ave 114 HR, but the NET cals burned were only 294.

    This certainly explains why the exercise burns I get do not equal the weight loss rate it should, according to the MFP calculators. Before I bought my HRM, I would enter an hour of light cycling and it would say I burned 700 cals!

    So a difference of over 400 calories! If I were eating back those calories, I would be gaining weight!

    I am also glad that I now average around 130 BPM for my workouts. Makes a huge difference.

    I think I will be using that calculator to figure my burns from now on.

    ETA, I actually rechecked my numbers and my HRM gave me 330 gross calories for an hour, so this calculator is almost exact with the PolarFT4!
  • Espressocycle
    Espressocycle Posts: 2,245 Member
    Maybe take your average heart rate for the exercise and run it through another calculator and see if they match up. If the heart rate is right but the formula the watch uses isn't, that could create a discrepancy.
  • peggymoney
    peggymoney Posts: 126 Member
    Thanks that was good info, I was looking into buying a hrm soon and heard polar is the way to go!
  • kohlmannj
    kohlmannj Posts: 1
    Calculate Calories: http://www.shapesense.com/fitness-exercise/calculators/heart-rate-based-calorie-burn-calculator.aspx

    YES!! This is a research-based calculator, and is the best one I've found to be applicable. It still overestimates a bit (due to the assumption of a high VO2 max), but it's pretty close.

    A very, very, very important point though is that the calculator is NOT correct for an average HR below ~60% of your max HR. That is also explained in the research paper that produced the calculator.

    The other point (that DebbieLyn63 highlighted above) is that if you're going to use this as a way to figure out how many calories you can "eat back" (by adding it to your basal metabolic rate) , be sure to use the NET calories burned, not the GROSS calories burned. There's a link to figure that out on the same page as the original calculator listed above.

    HRMs are all over the place, so it's hard to say how accurate yours is compared to any other. It depends on a lot of factors. My advice is to just use it to calculate average HR and exercise time, then plug those numbers in manually to the calculator listed above.

    Good luck!
  • sasu27
    sasu27 Posts: 51
    It's a Timex one that I bought a few years ago that I just dusted off recently. Better late than never, right?

    I had a Timex Ironman HRM with the chest strap and after getting crazy high readings from just doing simple tasks like cleaning (800 calories in a hour), I returned it and purchased a Polar HRM. There was a 400 calorie difference in the readings (polar reading lower). So for me, no I wouldn't trust Timex.
  • kensgirl2
    kensgirl2 Posts: 21 Member
    Calculate Calories: http://www.shapesense.com/fitness-exercise/calculators/heart-rate-based-calorie-burn-calculator.aspx

    YES!! This is a research-based calculator, and is the best one I've found to be applicable. It still overestimates a bit (due to the assumption of a high VO2 max), but it's pretty close.

    A very, very, very important point though is that the calculator is NOT correct for an average HR below ~60% of your max HR. That is also explained in the research paper that produced the calculator.

    The other point (that DebbieLyn63 highlighted above) is that if you're going to use this as a way to figure out how many calories you can "eat back" (by adding it to your basal metabolic rate) , be sure to use the NET calories burned, not the GROSS calories burned. There's a link to figure that out on the same page as the original calculator listed above.

    HRMs are all over the place, so it's hard to say how accurate yours is compared to any other. It depends on a lot of factors. My advice is to just use it to calculate average HR and exercise time, then plug those numbers in manually to the calculator listed above.

    Good luck!


    This is what I've started doing! I was going to buy a Polar HRM, but since you all have posted this site, I think I'll save the money and just plug in the numbers from my own. And it WAS an eye-opener! I *knew* that I couldn't've been burning as many calories as my HRM said I was, but dang!!! It made me feel like I was doing something!!!! :mad: But now I have a more realistic place to work from and won't be disappointed when my scale shows me something different than what I thought I had earned. *sigh*

    Thank you all for your input! It is greatly appreciated!!!!!!

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