Heart Rate Monitor Opened My Eyes, But I Have Questions

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CleanUpWhatIMessedUp
CleanUpWhatIMessedUp Posts: 206 Member
in Fitness and Exercise
I apologize if this is a little long. If you want, you can skip straight to the second paragraph for the question. The first paragraph is just a realization that I had. So first the realization that I had and then the questions. So, up until recently, I had just been going to the gym and working out and using the calories that the machines said I burned and entering that into MFP. No problem. I started to feel a little bit like I possibly wasn't working as hard as the machine said I was. Came on here and saw all of the people suggesting getting a HRM. I didn't really want to because they're kind of expensive. Anyway, I finally broke down and bit the bullet and got one. So I took it to the gym with me. What I wanted to do was see if it was really necessary (i.e. if there was any difference between what the HRM said and what the machine at the gym said). I got on one machine for about 10 minutes, looked at the heart rate and calories on the machine and looked at the heart rate and calories on the tracker and they matched exactly. Well at that point, I was starting to feel like the HRM was a waste. It was only telling me exactly what the machine was already telling me for free. Then I got on another machine and the heart rate on the machine and monitor was pretty similar, but when I finished my workout and looked at the calories, the machine had a much higher calories burned than the monitor. Now, I was baffled because I have been losing weight using the machine and eating back the calories but if the machine has been lying wouldn't that put me over the calorie limit. Then I realized that the reason I have been still losing weight is because of calories that I burn doing other things that I don't log (i.e walking almost a mile to the gym). I didn't even think about that before.

Anyway, my question is this, when I was on the machine it gave me the same heart rate as my heart rate monitor, however when the process was all said and done, the machine said I had burned way more calories than my heart rate monitor did. Can anyone explain this? I thought heart rate and calories burned were connected?

Replies

  • AmyRhubarb
    AmyRhubarb Posts: 6,890 Member
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    What kind of HRM is it and does it have a chest strap?
  • aleggett321
    aleggett321 Posts: 186 Member
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    Your HRM figures your calories burned based on the info you entered when you set it up (age, weight etc,) the machines just display a standard average that is non specific. They can vary by quite a lot. I trust my HRM over the machines.
  • cantfail
    cantfail Posts: 169 Member
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    How was the machine reading your heart rate? Most of the gym cardio equipment Ive been on lately read the heart rate from your chest strap transmitter automatically. That would be why the machine matched your heart rate monitor. I have always thought the calorie expenditure on cardio machines were notoriously wrong.
  • katykat79
    katykat79 Posts: 24 Member
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    Hi! Keep in mind that the machine you are working on does not have your personal stats that you entered into your watch (ie, weight, height, sex and age). Also, even if I put in weight and age as some machines allow, I have always found the machine calorie counts to be high. Go with your watch calorie count.
  • kethry70
    kethry70 Posts: 404 Member
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    a typical HRM has settings for your height, weight, age and gender which generally makes the calculation of caloric burn more accurate than just heart rate alone :flowerforyou:
  • CleanUpWhatIMessedUp
    CleanUpWhatIMessedUp Posts: 206 Member
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    The HRM is a Polar FT7.
  • brianpperkins
    brianpperkins Posts: 6,124 Member
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    Some machines factor in the heart rate data .. some don't and just use the HR as a display rather than a data point in their formula.

    No HRM measures calories burned. They all use a formula to estimate calories burned based on lab testing. How accurate your HRM's estimates are depends on how many data points it uses ... height, weight, age, gender, pulse, VO2 max, other fitness testing results, etc.
  • awesomek001
    awesomek001 Posts: 167 Member
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    Don't forget that inbetween the machines, you were moving. Maybe walking from one machine to another, maybe walking over to the fountain to get a drink. You heart rate is still up, so you're burning calories and your HRM is picking up those as well.
  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
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    First, heart rate is not directly related to calories burned. There is a known relationship between VO2 max and HR under specific conditions (steady state cardio) that allow for an estimation. Outside of this, it becomes less accurate.

    Also, keep in mind that because the cardio machine tracks HR, it does not mean it uses it to estimate calories burned which can be one reason for the difference.

    As others have mentioned, the what information you provided the cardio machine will be important as well.

    Here are a couple of great links that discuss the answers to your questions.

    http://www.myfitnesspal.com/blog/Azdak/view/the-real-facts-about-hrms-and-calories-what-you-need-to-know-before-purchasing-an-hrm-or-using-one-21472

    http://www.myfitnesspal.com/blog/Azdak/view/exercise-calories-sometimes-the-cardio-machines-are-more-accurate-404739

    http://www.myfitnesspal.com/topics/show/1044313-this-is-why-hrms-have-limited-use-for-tracking-calories

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