Calories Burned: MFP vs. Heart Rate Monitor

amperry328
amperry328 Posts: 21
in Fitness and Exercise
Hi everyone!

I know that everyone always says that the calories burned on MFP are always highly exaggerated. I recently purchased a Polar heart rate monitor to try to track my calories burned more accurately, and I was just curious if anyone has any insight as to how accurate they are.

For example, when I log 45 of spinning on MFP is says I only burn 308 calories. Last night when I went to my spinning class I wore my heart rate monitor and it said that I burned 422. If people are saying that the MFP calories burned are exaggerated then does that mean the heart rate monitors are even more inaccurate or in this case is MFP just too low for this specific activity?

I know that it's pretty much impossible to get a truly accurate number of calories burned, but I was just wanting to see if anyone has any thoughts or insight on this. Thanks in advance!

Replies

  • Aunt_Kiki
    Aunt_Kiki Posts: 47 Member
    I started using the HRM count instead of MFP's count in March. The numbers on my HRM are bigger than the ones on the website, and I've lost 18 lbs using those calorie counts. I think the HRM is more accurate as long as you program it to your own specifications (weight, age, etc). Either way, the key that works for me is not eating back too many exercise calories - some are ok, but not all.
  • TheSaoirseTree
    TheSaoirseTree Posts: 26 Member
    My experience is that with most machines (ellipticals, etc) I get the highest readings, then MFP, and then my HRM. The longer the workout on one machine or doing one exercise, the more off the numbers tend to be.

    Though, I do find that spinning on MFP is always a little lower than my HRM.
  • omma_to_3
    omma_to_3 Posts: 3,265 Member
    Your HRM will be more accurate than MFP because it's measuring your actual effort (assuming of course that it has a chest strap and you have it programmed correctly with your stats). What I have found is that MFP underestimates for larger people and overestimates for smaller people. When I first started using my HRM, my burns were a lot higher than what MFP said. Now, after losing weight and becoming more fit, MFP numbers are higher.
  • amperry328
    amperry328 Posts: 21
    Thanks for the responses so far! I was just thinking that 308 for spinning seemed low and that maybe 422 was more accurate, but who really knows for sure :)
  • OccamsDisposableRazor
    OccamsDisposableRazor Posts: 49 Member
    Your HRM will be more accurate than MFP because it's measuring your actual effort (assuming of course that it has a chest strap and you have it programmed correctly with your stats). What I have found is that MFP underestimates for larger people and overestimates for smaller people. When I first started using my HRM, my burns were a lot higher than what MFP said. Now, after losing weight and becoming more fit, MFP numbers are higher.

    ^^ I agree with this. I have been using MFP and a HRM for about a year and have noticed the same trend. I haven't had a lot of weight to lose, but I've been working on toning up and increasing overall fitness.

    For example, when I first started zumba, I'd burn 700-800 calories in an hour according to my HRM. At 150 lbs, MFP would estimate 600 calories - a substantial difference where I actually burned a lot more than MFP estimated.
    Now in that same class, I'm averaging 500-550 according to my HRM. I'm only 5 pounds lighter, but my body is just fitter. MFP now estimates I burned 579 - MUCH closer to accurate, but now I actually am consistently burning FEWER calories than MFP estimates.
  • scubasuenc
    scubasuenc Posts: 626 Member
    Interesting the observation of how the difference between MFP and the HRM calorie counts change with weight.

    I purchased my HRM in January, and I'd already lost 30+ pounds on MFP. I was using the MFP calorie counts but per my doctor's recommendation I was not eating back my exercise calories. As soon as I started using my HRM I found that MFP was always very high for everything except walking. For some activities like riding my stationary bike or skin diving the MFP counts were off by a factor of 2 or 3. As I have lost weight the MFP and HRM calorie burns have gotten closer, but MFP is still always significantly higher. My stationary bike is configured for my statistics and it is consistently between the MFP and HRM numbers.

    I use the MFP numbers for strength training since my HRM is useless for that and everyone says the MFP numbers are consistently on the low side. Other than that, if I'm not wearing my HRM I usually take half of the MFP or an estimate based on the last time I wore my HRM for that activity. I'd rather be on the low side than over estimate.

    What is interesting is that I have also calculated my TDEE based on what I'm eating and my actual weight loss. When I compare that to the TDEE I calculate based on what I have entered in for exercise on MFP it is pretty close. My actual TDEE is usually a little higher. In other words, I consistently lose a little more than MFP predicts.

    I find the numbers fascinating, but I've stopped sweating the details. Once I started calculating my TDEE and found it was in line with the standard calculators I switched to eating the same amount every day as a deficit from my TDEE. The main reason I continue to track my exercise calories is that I want to make sure I am exercising enough to hit my TDEE.
  • omma_to_3
    omma_to_3 Posts: 3,265 Member
    Interesting the observation of how the difference between MFP and the HRM calorie counts change with weight.

    I purchased my HRM in January, and I'd already lost 30+ pounds on MFP. I was using the MFP calorie counts but per my doctor's recommendation I was not eating back my exercise calories. As soon as I started using my HRM I found that MFP was always very high for everything except walking. For some activities like riding my stationary bike or skin diving the MFP counts were off by a factor of 2 or 3. As I have lost weight the MFP and HRM calorie burns have gotten closer, but MFP is still always significantly higher. My stationary bike is configured for my statistics and it is consistently between the MFP and HRM numbers.

    I use the MFP numbers for strength training since my HRM is useless for that and everyone says the MFP numbers are consistently on the low side. Other than that, if I'm not wearing my HRM I usually take half of the MFP or an estimate based on the last time I wore my HRM for that activity. I'd rather be on the low side than over estimate.

    What is interesting is that I have also calculated my TDEE based on what I'm eating and my actual weight loss. When I compare that to the TDEE I calculate based on what I have entered in for exercise on MFP it is pretty close. My actual TDEE is usually a little higher. In other words, I consistently lose a little more than MFP predicts.

    I find the numbers fascinating, but I've stopped sweating the details. Once I started calculating my TDEE and found it was in line with the standard calculators I switched to eating the same amount every day as a deficit from my TDEE. The main reason I continue to track my exercise calories is that I want to make sure I am exercising enough to hit my TDEE.

    You make a good point on specific exercises and MFP. I only use the walking/running/biking options in MFP so my observations are around those. Biking on MFP does seem slightly higher than it should be though. I've heard other things, like elliptical, are off by a lot more.
  • amperry328
    amperry328 Posts: 21
    Thanks for all the feedback! I think I will just try to not worry about the exact number so much and just go for a happy medium. I have started to try to eat my exercise calories back, but didn't want to overdo it by eating back too many. I've seen many suggest eating back 50% or so, so I would probably try that.

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