HRM vs MFP

dawnm92
dawnm92 Posts: 56 Member
edited October 2 in Fitness and Exercise
I started using a heart rate monitor about two weeks ago. It is a Timex with a chest strap and watch and it has you input a bunch of info including your weight, age, max HR, and a HR range you want to stay in (for example, 60-85% of max).

Anyway, it consistently shows that I'm burning more calories for an activity than MFP estimates. For example, one of the things I do a lot is walk in the park. I walk at a brisk pace (estimated 3.5 mph) and there are quite a few hills on the path I take. Today I walked for 40 minutes at lunch time. It was about 95 degrees, closer to 100 with the heat index, so my heart rate was even higher than usual.

MFP counts 40 min at 3.5 mph uphill walking as 415 calories burned.

My HRM provided these stats - 40 minutes, avg HR 130 (71% of max), peak HR of 148, 681calories burned.

That's significantly different than MFP's estimate. Part of that may be the heat which made it a much harder walk. A few days ago, my stats for the same 40 minute walk were avg HR 117, peak HR of 146, 543 calories burned. I walked slower that day and it was about 15 degrees cooler outside too.

However you look at it, there is always a significant difference between MFP and my HRM. Who do I believe?

Replies

  • rainbowcandy2004
    rainbowcandy2004 Posts: 44
    I think MFP just calulates based on a 3.5 pace for the entire time. I have a step counter that I had to input weight and all that good stuff and it says I burn more calores than MFP because my pace changes so I would go with the heart rate monitor. Thats just me.
  • Jemmuno
    Jemmuno Posts: 413 Member
    I would believe my HRM. MFP is just an average and doesn't take into account your weight and also MFP doesn't know your heart rate during your work out and how hard your working, as well as outside factors such as heat. Use the number your HRM gives you.
  • My1985Freckles
    My1985Freckles Posts: 1,039 Member
    Believe your HRM.

    MFP is NOT accurate. The formula for calories burned is driven by the average heart rate over the duration of the workout. If your average heart rate is higher then you burn more calories in the same amount of time. Trust your HRM, it is accurate.
  • raisingbabyk
    raisingbabyk Posts: 442 Member
    which HRM do you have? I've been looking at some timex ones and im not sure which to get
  • alison2429
    alison2429 Posts: 236 Member
    Definately the HRM would be more accurate.

    But HRM usually reads less than MFP in my experience.
  • dawnm92
    dawnm92 Posts: 56 Member
    Definately the HRM would be more accurate.

    But HRM usually reads less than MFP in my experience.

    I'm just guessing here but maybe your HRM reads less than MFP for you because you weigh much less than I do? I don't know exactly what you weigh but your ticker looks like you are close to your goal weight. I am about 100 pounds above that. So maybe MFP is estimating in between someone as small as you and someone as heavy as me.... So for you MFP's estimates are too high and for me they are too low. Seems logical to me anyway.
  • dad106
    dad106 Posts: 4,868 Member
    Actually in this one case, don't believe the HRM.

    In order to get a true calorie estimate you need to enter all your info(age weight height and gender) not just weight, max and lower heart rate. The HRM thinks you are a male, and thus is giving you the calorie burn of a male.

    I'd return it ASAP for one that lets you enter all the info.
  • dad106
    dad106 Posts: 4,868 Member
    which HRM do you have? I've been looking at some timex ones and im not sure which to get

    Do not get a TImex.. They are crap at estimating calories.

    Polar is a much better option.. either the FT4 or the FT7.
  • Alegria79
    Alegria79 Posts: 133 Member
    Generally it's reasonable to accept your HRM as more accurate, but they may both be off. Everyone is different, but the numbers seem a bit high for a 40 minute walk. I used my Garmin HRM for a 1 hr walk last week (distance was 4 miles) and I burned 305 calories. My polar HRM (with chest strap) would have given me about 450-500 calories for the same walk. That's one of the reasons I stopped using my Polar - it seemed to overestimate by about 25%. It took a 3 month plateau for me to figure that one out :smile:

    Anyway, if you're using the higher number and you stop losing weight, it may be overestimating, so switch to the lower one. If you are using the HRM info and losing weight, it works for you and you have no problem!
  • dawnm92
    dawnm92 Posts: 56 Member
    which HRM do you have? I've been looking at some timex ones and im not sure which to get

    I have the Timex T5G971. I researched some on Amazon a couple of months ago and at the time it seemed like the best one for the price. I've heard good things about the Polar HRMs (here on MFP) but I've never used one. I just know that they cost significantly more than the Timex I got.

    This one has been very good for me so far. There are two things I don't like about it though.
    1) You have to be wearing the chest strap to even input your personal info -- the book doesn't tell you this and makes for a very frustrating setup process.
    2) You can't see both your HR and the duration of your exercise on the screen at the same time (unless I haven't figured that part out yet), which is very irritating. I wear a separate watch and look like a dork with two watches just so that I can track my time while tracking my heart rate.

    Even so, for the $35-40 price range it has been very good so far! If you want to spend a little more, you might consider one of the Polar models, but make sure it has BOTH duration and HR on screen because I read in one of the forums here that one of the models has the same issue as mine has.
  • dawnm92
    dawnm92 Posts: 56 Member
    Actually in this one case, don't believe the HRM.

    In order to get a true calorie estimate you need to enter all your info(age weight height and gender) not just weight, max and lower heart rate. The HRM thinks you are a male, and thus is giving you the calorie burn of a male.

    I'd return it ASAP for one that lets you enter all the info.

    Someone else briefly mentioned gender as a setup option...but I tried to research that online to see which HRM's include that option and what the calorie burn difference is and I came up with nothing. Do you have a link to some resource that explains how this is different?

    I'm stuck with this HRM for the time being (would love to make my next one a Polar) so it would be great if I can figure out the % difference between male and female so that I can use the estimate the HRM provides and then figure a more accurate estimate for myself as a woman.

    As for which calorie estimate I've been using - I've been using MFP estimates for months and have never changed that even though I started using this HRM recently. I was just curious because I had been stuck at 230-232 pounds unable to lose anything when using MFP's recommendations and exercising about 8 hours a week! I lost zero pounds in June and July and the first half of August.

    It wasn't until I got this HRM and realized that I may be burning significantly more calories with all of my activity which made me question my calorie intake. According to MFP my intake was 1300-1500 net per day. When I recalculated with HRM numbers, it put my net calories below 1200, often below 1000. I increased my calorie goal in MFP by several hundred per day and continued using their exercise estimates and I have finally started losing weight again - 2.5 pounds this week!
  • seasonalvoodoo
    seasonalvoodoo Posts: 380 Member
    Hmm, that does seem a little high, but it may not be.

    I would tend to trust the HRM.

    I use a Sportline 1060 Duo (Women's) and it is always reading less than what MFP says for most activities. That one let's me enter in my height, age, weight, gender, and walking and running stride length.
  • dad106
    dad106 Posts: 4,868 Member
    Actually in this one case, don't believe the HRM.

    In order to get a true calorie estimate you need to enter all your info(age weight height and gender) not just weight, max and lower heart rate. The HRM thinks you are a male, and thus is giving you the calorie burn of a male.

    I'd return it ASAP for one that lets you enter all the info.

    Someone else briefly mentioned gender as a setup option...but I tried to research that online to see which HRM's include that option and what the calorie burn difference is and I came up with nothing. Do you have a link to some resource that explains how this is different?

    I'm stuck with this HRM for the time being (would love to make my next one a Polar) so it would be great if I can figure out the % difference between male and female so that I can use the estimate the HRM provides and then figure a more accurate estimate for myself as a woman.

    As for which calorie estimate I've been using - I've been using MFP estimates for months and have never changed that even though I started using this HRM recently. I was just curious because I had been stuck at 230-232 pounds unable to lose anything when using MFP's recommendations and exercising about 8 hours a week! I lost zero pounds in June and July and the first half of August.

    It wasn't until I got this HRM and realized that I may be burning significantly more calories with all of my activity which made me question my calorie intake. According to MFP my intake was 1300-1500 net per day. When I recalculated with HRM numbers, it put my net calories below 1200, often below 1000. I increased my calorie goal in MFP by several hundred per day and continued using their exercise estimates and I have finally started losing weight again - 2.5 pounds this week!

    I had the HRM you have.. so heres a little comparison and I'll post a link in a bit that explains more.

    Female, 5'9, weighed 160 at time, and 23 yrs old
    Did treamill for 30 min at speed of 3.0 and 15% incline
    Time:581 calories burned
    Polar:300

    281 calorie difference.. and thats a lot!

    That 2.5 though could be water, fat.. alot of variations.
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