How to test HRM for how accurate calorie burn is

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  • JorgeGonzales
    JorgeGonzales Posts: 27
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    I will try this. Thanks
  • heybales
    heybales Posts: 18,842 Member
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    did you try it with your polar? was it accurate? curious to know.. I have a polar too.

    Someone on 2nd page reported their Polar test, not great.
    Other guy did on other thread - 20 min test at mere 120 bpm, Polar was 11% below.

    You can't compare to others, as your fitness level is your own.

    I never did test that I recall, and no treadmill to use now or I'd test it. I actually should test it on my next run.

    I used the site indicated with an outdoor run, and stats on total elevation gain (and since I came back down, total loss), which both count as grade, so doubled.

    So total gain x 2 / miles / 5280 x 100 = grade %
    Had my mileage, had my time, had my pace, had my weight.

    2 calories different than my personal VO2max formula. And that was very hilly route.

    Just did another run today, flatter, actually Jog and walk intervals, same thing, a tad bit of heat elevated HR, so my formula was about 20 over calculated.

    My Garmin remains a problem since there is no way to tell it your VO2max stat, so it's used for just getting all the other stats that I like.

    So maybe I can test the Polar actually.
  • bellesouth18
    bellesouth18 Posts: 1,069 Member
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    Bumping to have the information.
  • heybales
    heybales Posts: 18,842 Member
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    Thanks heybales for providing the link to this page on Pu's profile! I will look into this, although my current conversion factor seems to be acceptable for now.

    That is, I attempted to calibrate to a treadmill while running and came up with a multiplicative factor of 0.65 for my cheap Timex HRM. The beats per minute is accurate thus far.

    Question: does a low resting heart rate and a quicker recovery time tend to indicate that the person is in better shape?

    Low resting HR indicates heart can pump enough oxygen around for resting level requirements at lower value. Good fitness level.

    Quick recovery time indicates same thing.

    If you really want better accuracy, and you have treadmill, come up with your own personal HR formula.
    Depending on current fitness level, may improve enough to do this monthly or two.

    http://www.myfitnesspal.com/blog/heybales/view/getting-your-personalized-calorie-burn-formula-663625
  • Jennifer_Lynn_1982
    Jennifer_Lynn_1982 Posts: 567 Member
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    bump
  • AnnPT77
    AnnPT77 Posts: 32,131 Member
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    Glad you re-linked this in a current thread. It's a gem, as with most of your helpful posts. Thanks!
  • NorthCascades
    NorthCascades Posts: 10,970 Member
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    This is an old thread but the info is still relevant and some of the posters are still here. 🙂

    I tested against a direct force power meter. I've found the HRM is almost always over, by up to 40% but usually much less. In one case of was off by much less than 1%. No obvious way to tell where any ride was along that range, intervals vs steady vs the way people normally ride bikes made no observable change to the HRM's accuracy.
  • heybales
    heybales Posts: 18,842 Member
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    As I get out of summer a HR-based formula using a VO2max estimate starts getting within 5% of power meter. Like when I'm not sweating off 5-10 lbs for 1-2 hr ride.
  • djaxon1
    djaxon1 Posts: 82 Member
    edited November 2020
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    I'm glad calories aren't my priority - it's a minefield !
    Putting in 3mph ,60min level walk , 200lbs - exrx gives 315
    42.195 gives 513cals ? ?
    keisan 276 , must put in details so 45yr/5'9
    shapesense 360
    caloriesburnedhq. 333
    healthline 260+

    For a much harder incline walk my old treadmill reads low but no inputs at all
    Huawei health app with cheap wrist band reads low -ish
    Old Polar with vo2 input reads middling , same for myworkouts app , both with chest straps.
    exrx and 42.195 both give highest cals results by 10-15%

    This blog "Intensity not HR" as title , https://www.myfitnesspal.com/blog/Azdak?month=201005
    States HR is not a direct indicator of caloric burn.
    And I get a lot of cardio drift as described here - https://www.myfitnesspal.com/blog/Azdak?month=201106
    30% more cals "burned" in 2nd half hour of a steady state 1 hr workout !" As stated - No way !

    There seems a big disconnect with HRM's calorie estimates
  • AnnPT77
    AnnPT77 Posts: 32,131 Member
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    djaxon1 wrote: »
    I'm glad calories aren't my priority - it's a minefield !
    Putting in 3mph ,60min level walk , 200lbs - exrx gives 315
    42.195 gives 513cals ? ?
    keisan 276 , must put in details so 45yr/5'9
    shapesense 360
    caloriesburnedhq. 333
    healthline 260+

    For a much harder incline walk my old treadmill reads low but no inputs at all
    Huawei health app with cheap wrist band reads low -ish
    Old Polar with vo2 input reads middling , same for myworkouts app , both with chest straps.
    exrx and 42.195 both give highest cals results by 10-15%

    This blog "Intensity not HR" as title , https://www.myfitnesspal.com/blog/Azdak?month=201005
    States HR is not a direct indicator of caloric burn.
    And I get a lot of cardio drift as described here - https://www.myfitnesspal.com/blog/Azdak?month=201106
    30% more cals "burned" in 2nd half hour of a steady state 1 hr workout !" As stated - No way !

    There seems a big disconnect with HRM's calorie estimates

    5'9", male, 200lbs, age 45: Estimated TDEE at sedentary, around 2200 calories daily, best guess. (Could be wrong, sure - high or low.)

    Lowest exercise calorie estimate I see in your post: 260 calories.
    Highest exercise calorie estimate I see in your post: 513 calories.

    Maximum difference in estimates, 253 calories. 11.5% of base TDEE.

    Every day? Then if the most minimal normal calorie deficit of 250 daily (half a pound a week), and the lowest estimate is right (no reason to believe it is, vs. a higher one), you wipe out your deficit and maintain weight. At loss goal of a pound a week, you lose half a pound instead of a pound.

    In a context where you sensibly adjust intake based on results? No harm, after the first few weeks (before adjusting).

    Less than every day exercise? Less effect.

    "Minefield"? "Big Disconnect"? Meh. Close enough for gubmint work.
  • djaxon1
    djaxon1 Posts: 82 Member
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    So . . . seems calorie estimate accuracy isn't such a big issue . especially where you adjust intake based on results.
    A lot of posts on here do seem concerned with let's say the "clinical accuracy" of their wearable tech.
    Of course , I always check the "inaccurate" calorie estimate after a workout !
  • AnnPT77
    AnnPT77 Posts: 32,131 Member
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    djaxon1 wrote: »
    So . . . seems calorie estimate accuracy isn't such a big issue . especially where you adjust intake based on results.
    A lot of posts on here do seem concerned with let's say the "clinical accuracy" of their wearable tech.
    Of course , I always check the "inaccurate" calorie estimate after a workout !

    It can be a big deal, but it's situational. Using a gross calorie estimate (includes BMR) for a multi-hour low burn activity when you really want net, believing the occasional machine (or exercise video) that gives massive over-estimates, maybe believing HRM estimate for long sessions of interval, 'HIIT', weight circuits - could be a problem.

    Depends on the numbers. If my sedentary TDEE or NEAT was 1500, and I regularly recorded 1000 calories for something that was really 500, that starts to be an issue.

    Adjusting intake based on results can help, but big errors could risk underfueling or subpar nutrition via the magnitude of the adjustment.

    IMO, relative accuracy is worth pursuing, but need to keep the relative magnitude of numbers in mind, not stress or obsess over manageable amounts of uncertainty.

    Hence the value of threads like this one, where people with sound knowledge (heybales, not me) help us try to understand better.
  • heybales
    heybales Posts: 18,842 Member
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    Oh Ann, your knowledge on the matter is excellent and shows in that synopsis.

    I always use the example of you could be 100% inflated calorie burn for your hard calisthenics program, but if it's only 15 min 3 x weekly and you are active otherwise, big whoop.

    But I'm very sedentary, and I do some longer harder workouts, and seeing differences of 400 total calories per session x 4 weekly becomes meaningful, but there are variances to the week so it changes too. As you say, would be about impossible to adjust based on weight results, of which I only have about 2 valid weigh-ins available per week.
    Weight results for me would be delayed and would confirm something is off, but not useable for how much to adjust.

    All the info I've ever presented on calories and HRM's and formula's has been after researching it for use in my case because I needed it and willing to dig, I'll share it - but I also see (better) now how necessary (or not) it's needed for others. Like many others, health and fitness has become a hobby too.

    This thread I think is actually of use now for what appears to be many getting 15-20K steps in, about 8-10 mile in my case of walking, in normal days, and their activity tracker is doing HR-based calorie burn in a bad range, and they don't do much of other workouts yet. And wondering about not losing anymore.
    Now in many of their cases it seems normal lifestyle, so adjusting the eating based on weight results is great. But many women still need that month of change and rolling avg before you have an actionable figure. As you say, might as well hone in on accuracy if you can, it get's easier like using a food scale.
  • AnnPT77
    AnnPT77 Posts: 32,131 Member
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    Thank you for the kind words, heybales. (I just don't want to post implying I'm a credentialed expert, or even anything like a hobby-level deep specialist.)

    This is off-topic, for which I apologize, but I feel like a foundation problem is that many people disliked and were bad at "story problems" in K-12 math classes. Those skills (plus a bit of the much-deprecated algebra 😉) are really helpful in successful calorie counting, IMO. The whole process is just one big, complicated story problem.

    The skills of estimation (including some info about relative magnitude of estimating errors) was elementary or middle school curriculum, IIRC.

    I'm lucky, even though also math challenged: Even from childhood, I was relatively decent at story problems, working out how to solve the problem. What I'm awful at is arithmetic, always forget to carry the one, and times tables still are a shifting landscape. Common availability of calculators started about when I graduated from high school, and has been a lifesaver, for me. 😆

    Thank you for so routinely sharing your knowledge here - I've learned a lot from your posts.

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