HRM v Runkeeper v MFP for walking calorie burn

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jennyluck
jennyluck Posts: 2 Member
in Health and Weight Loss
Hi all, I've been using MFP since March 2012, but this is my first time posting on the forums.

I recently (yesterday) bought a nifty Polar FT4 HRM thinking it would help me more accurately log calories burned as I get closer to goal (20lbs to an overweight BMI!). Based on a little slow down in weight loss I guessed that I've been overestimating calories burned, which will make more of a difference the less I have to lose (yes lose, NOT loose), particularly since I eat back most of my exercise calories.

I did the elliptical last night for 65 minutes, with my weight and age in both the machine and the HRM, and got a calorie burn of 780 from the elliptical and 570 from the HRM. MFP’s estimate was around 780 as well.

Since I’ve seen in the forums that ellipticals and MFP estimates may be pretty inaccurate (~20% plus or minus), I reluctantly logged the 570 (27% less) calories. Darn accuracy.

This morning I took my daily walk to work. This takes me 44 minutes, and it’s 2.23 miles of relatively flat city streets walking about 3mph. I’ve been logging it with MFP’s estimate since I started (which is about 200 calories right now). I also have RunKeeper, and that estimated 221 calories today with an average speed of 3mph.

So this morning I also wore the HRM, and it tells me that I burned 97 calories. That’s off by more than 50% from MFP. I have to admit, that was a little disappointing.

And then I got to thinking (or maybe overthinking):

The HRM (and the machines at the gym) don’t really take into account the calories you burn in your everyday life. So I went into MFP and saw that as a 30 year old with a desk job who’s 5’2” I should burn 1870 a day from normal sedentary activity.

1870/ 24 hours = 78 calories an hour, or 57 in 44 minutes.

So, if I wanted to be anal I would log 97 burned from the HRM – 57 calories of normal activity (disclaimer, I’ve never subtracted “normal activity” calories since I started, and it hasn’t hurt me, but stay with me here).

That leaves me 40 exercise calories burned for a 44min walk at 3mph. That’s 40 calories more than just sitting at my desk at work for those same 45 minutes, and that seemed low.

So, great MFP hive mind… am I grasping at straws, or is my math wrong? My FT4 was definitely an investment so I want to make sure I’m using it right, and that it’s a good tool that actually helps me.

A little more info that may help: I’ve been logging both food and exercise since March 2012 pretty successfully. I have MFP set to sedentary and eat back most of my exercise calories, so how much I’m burning is pretty relevant. I mainly do cardio (walking, jogging, elliptical, swimming laps). Yes, I want to lift a little (or a lot, go big or go home) at some point, but I still have enough to lose I shouldn’t need to focus on body recomposition for progress. I switch it up so I haven’t been doing the same thing every day.

I also am married to an IT guys, so I checked the basic “well, is it plugged in” type stuff- my weights/heights/ages match in all my devices and programs.

As a thanks for making it to the end of this very long post, please enjoy this kitteh!

Moo_zps35321122.jpg

Replies

  • Ninkyou
    Ninkyou Posts: 6,666 Member
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    The HRM isn't made to read your entire day's expenditure. It's made for steady state cardio. It's also an estimate of your caloric burn (albeit way more accurate than the machines/MFP). Record what the HRM gives you for burn. Also, make sure your user settings are entered accurately on the watch. Don't forget to update it when you lose weight too!

    In short, yes the machines/MFP/Runkeeper all typically overestimate burns. Go with the HRM for your exercise.
  • joannadalina
    joannadalina Posts: 112 Member
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    What a great post. I have been thinking about purchasing the Polar HRM for more accurate readings. I currently use RunKeeper but have been thinking about investing in a Polar. Please keep me posted, will send request :)

    Best of Luck,
    Joanna
  • Ninkyou
    Ninkyou Posts: 6,666 Member
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    I also wanted to say I have the Polar FT4... and I love it. :)
  • Mokey41
    Mokey41 Posts: 5,769 Member
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    Try picking up the pace when you walk and keep an eye on your HR. If you aren't significantly elevating your HR it won't be accurate although it usually shows a larger burn rather than smaller. 3mph is a pretty slow walk for getting much of a calorie burn.

    It is true that a HRM doesn't deduct your BMR from it's calculation. Figure your BMR not your TDEE divided by 24 to get your basic hourly rate. TDEE is expecting some movement in order to get that number so it's higher.
  • coolraul07
    coolraul07 Posts: 1,606 Member
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    The HRM isn't made to read your entire day's expenditure. It's made for steady state cardio. It's also an estimate of your caloric burn (albeit way more accurate than the machines/MFP). Record what the HRM gives you for burn. Also, make sure your user settings are entered accurately on the watch. Don't forget to update it when you lose weight too!

    In short, yes the machines/MFP/Runkeeper all typically overestimate burns. Go with the HRM for your exercise.
    ^THIS. I have a FitBit One (FBO) and a Polar FT7; the former is for all-day monitoring and the latter is for steady-state cardio. FBO automatically syncs with MFP, so all I have to do is manually enter HRM results as necessary and both sites are sync'd/updated.
  • Mr_Knight
    Mr_Knight Posts: 9,532 Member
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    Running:

    Gross calories burned = 0.75 * body weight in pounds * miles run (not walked - run)
    Net calories burned = 0.63 * body weight in pounds * miles run (not walked - run)

    For walking, use 0.53 and 0.30 as the multipliers (yep, walking sucks as a net-calorie burner unless you go out for multiple hours).

    Note the absence of heart rate in those equations. HRMs are, outside of strict parameters which most on MFP don't fit, poor estimators of calorie burn. I use an HRM for running and cycling - but not for calorie burn, rather for heart rate monitoring. Which, oddly enough, is the function it is actually designed to do. :)
  • foxylady522
    foxylady522 Posts: 80
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    Yes, it is disappointing when you realize that your HRM is accurate and the machines, MFP, and Runkeeper give you a higher burn count than the HRM. However, I always go with my Polar FT4 reading. I have found it to be accurate in the sense that I am able to log all of my exercise, eat back those calories, and still have weight drop. I found that knowing what my HRM said for my calories burned/ heart rate has made me rethink how I perceive my effort in a work out :)

    Keep with it! The HRM is a good investment and you will eventually appreciate it's honesty :)
  • jennyluck
    jennyluck Posts: 2 Member
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    Thanks for the feedback, all! I was looking for other ways to calculate walking calories, and I found this http://www.walkinginfo.org/faqs/answer.cfm?id=1227, but that would be even higher (182-215 depending on which calculator I use).

    I definitely appreciate the honesty of the HRM (that's why I got it!), and I expected to find a difference, just the difference specifically related to walking surprised me. I guess I thought I'd burn more than 40 additional calories in 44 minutes, even if it wasn't speed-walking, in comparison to the sitting-on-my-butt I do the rest of the day at work.

    It sounds like the happy medium would be logging 97 calories for 44 minutes of walking at 3mph. If I walked to and from work, plus went to the gym, I'd be overestimating calories burned by about 400+ that day pre-HRM. I can see this will definitely keep me honest...

    Thanks again!
  • sarah456s
    sarah456s Posts: 98 Member
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    I bought a Polar HRM a couple of years ago when I was getting serious about getting fit. [And then I injured myself and totally slipped backwards, but that's another story.]

    At the time, my resting heart rate was in the 50's, so I was pretty fit in the cardiovascular sense. I found a 3mph walk would not raise my HR into anything remotely approaching a decent calorie burn. I'd have to push it into a very brisk walk or a run to push my HR up. So, I think if you're used to exercising and also used to walking to work, then I would believe that your burn is significantly lower than is estimated by MFP, particularly for slow activities like walking.

    One option might be to count yourself as "lightly active" for the purposes of estimating your TDEE. And then not count the walking to work separately. Of course, then you'll have to walk to work every day, no slacking!

    I keep thinking I need to dig my HRM out from wherever it's hiding.
  • fyoung1111
    fyoung1111 Posts: 109 Member
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    I use MFP, Runkeeper, and Fitbit all synced together. I only run every other day and usually put in 10+K then. On running days, I use a 60beat Bluetooth HRM which talks to Runkeeper on my iPhone.

    I have never checked to see if Runkeeper awards me with more or less calories burned when I wear the HRM. I've been presuming it's more accurate that way and the primary reason I wear the HRM is to prevent myself from overdoing it (or perhaps for the security of knowing that I am NOT overdoing it).

    My Fitbit One is with me always (except the shower). On today's 9.83 K run, Runkeeper rewarded me with a 747 calorie "bonus" compared to 938 that Fitbit gave me over the same 90 minute period of time. My Basal Metabolic Rate (BMR) as reported by http://www.bmi-calculator.net/bmr-calculator/ is 1,533 calories per day or 64 per hour so Fitbit is obviously giving me credit for a little more than just being supine. MFP decided to give me the 747 calorie credit. Seems that MFP is only handing out credits for "extra effort".

    Fitbit gave me 1134 calories worth of credit just for sleeping and sitting on my bum between midnight and noon. That 100 calorie credit for doing little or nothing at all explains a lot of the 191 calorie difference between the Fitbit and Runkeeper credits over an hour and a half.

    On days that I don't run but do move about a lot, I don't wear the HRM and don't fire up the Runkeeper app. I do however usually receive a small MFP calorie "bonus" from Fitbit for not being a total desk jockey or couch potato. For me, these three apps (MFP, Fitbit, and Runkeeper) combined with three pieces of hardware (iPhone4S, Fitbit One, and 60beat HRM) constitute the ultimate fitness/weight loss team. My expensive Polar and Garmin devices are gathering dust.

    While I have an intellectual curiosity about how MFP chooses its calorie burn information from RunKeeper relative to FitBit, as a practical matter I don't care. All of the numbers are doubtless wrong but any of them are also good enough. I'm just happy that MFP is smart enough NOT to give me credit for BOTH devices.

    So ... bravo myfitnesspal for getting that one right! Now put that same team of crack coders on fixing the unholy mess that is your Recipe Nutrition Calculator and I'll be truly content.

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