Polar HRM calorie burn estimate accuracy - study

I have the FT60, and I like it!

I am always amazed at how people will dismiss exercise machine calorie numbers out of hand but will accept HRM calorie numbers as "truth" without any question whatsoever.

Whoever designed human brains had a wicked sense of humor.

Do you think the machine values are perhaps way off because the calibration of actual speed is bad?

I was on a treadmill at gym that was flashing a warning about lubricating the belt or such, so I told the staff.
"we'll reset the warning"

Not we'll fix it, not they need oil from time to time, ect. We'll get rid of the warning.

Made me wonder if they ever did the required re-calc after so many belt miles. I got the manual for it awhile back to use the trainer's features on it (nothing like saving your interval routine under a trainer's code for access later, if I get that machine anyway!) and noticed re-calc is supposed to be part of normal routine on it.

If belt is off, then speed is off, then calc's is off. Because I just don't see why they wouldn't use the standard calc's for MET's when they know the weight, pace, incline, ect and could nail the calories needed for that effort.

I don't think treadmill values are "way off" at all. In fact, I think for most commercial treadmills (that require that you input your weight) the calorie readings for walking are as accurate as you can get w/out a metabolic cart (assuming that you do not hold on to the handrails).

The values for running start are more of an overestimate (15%-25%), due to inherent errors in the ACSM equations and differences in the mechanical costs of running on a treadmill vs outside.

Commercial treadmills are calibrated at the factory and speed/elevation controlled by computer sensors. To my knowledge, they cannot be manually "recalibrated" , nor should they be (I am not familiar with every brand of treadmill--I know this is true for Life Fitness).

It stands to reason that with belt wear, one might experience a decrease in accuracy, but it would not be that large--certainly much smaller that the variations experienced with an HRM. In fact I often tell people to use the calorie numbers they get from walking on a treadmill as a quick way to judge the accuracy of their HRM settings. If you are working at a steady-state level, not holding on, in a 60%-70% intensity range and there is a big discrepancy between the treadmill calorie number and your HRM, it is much more likely the the HRM numbers are the more inaccurate.

With cross trainers, it's not the same. That's because the cross trainer algorithms are usually not machine-specific--they use one from another modality (e.g. walking or running). The only company I know that has developed machine-specific energy prediction algorithms for some of their cross trainers is Life Fitness. Unfortunately the most common model seen in health clubs uses an older algorithm developed before LF had their own testing lab and so it greatly overestimates calories. But if you are fortunate enough to be at a facility with the newer "elevation" series cross trainers, those calorie numbers should be very accurate.

I have a Polar FT40 coming - I purposely got it for the fit test and a bit more accurate burn (though I know nothing is truly accurate). I plan on also using the spreadsheet. I'm just looking for better numbers than MFP or MapMyRun/Runkeeper - they are all over the place!

Agreed. I think it must be the active selection process. The machine numbers are just there. MFP numbers are just there. But the HRM numbers....research was done on which is best, questions were asked about accuracy, threads were read about user experiences, and up to $100 was spent on the final selection. With all that effort put in, whatever random number the device spits out is not just true, but TRUTH.

Excellent point.

It must be right because I spent the money on it.

For the majority that seem to ask about recommendations though, I'd bet the research part of it didn't happen, merely the recommendation part of. The questions on MFP looking for a HRM never seem to sound like the least bit of research was done first, which means merely going on popular vote, that happened to notice your thread, at that time of day, from ones that you don't know if they have any idea.

I know I've asked several what their avg HR was for a workout, and they are like, that stat is there? I can give you my calorie burn, does that tell you? Huh, I have Polar too, all those stats are there after a workout.

For most, asking other people what HRM actually counts as the *research*.

The thing that amuses me most is how quickly people bail on their original argument for getting the HRM. Poster after poster says "Don't trust MFP, the burns are too high!" and then you read a thread where the OP says "MFP says 300 cal, my HRM says 550" and every single response says "TRUST THE HRM, use the higher number". Wait, so MFP estimates way too high, except for when it's way too low? Literally any number the HRM spits out, high or low, is taken as gospel, even tho there isn't a source to confirm the numbers with.

I really like the idea of checking it with walking on the treadmill. What's funny about the HRM stuff- I remember I got my first HRM in college circa 2003ish, when I was taking running as a fitness elective- it came with the tuition for the class. The purpose of it was to work on zone training, learn about VO2max, etc. It had a calorie setting, but the teacher/coach told us to use it to gauge performance only- as in, the gross number doesn't mean anything. So I've used it for years that way. Then I got to MFP and saw 8 million posts about using HRMs, and I remember one of my first posts was asking if everyone was using zone training, and how they could possibly be using it for DVDs and whatnot- was I ever surprised to find out the HRM had become exclusively a calorie counter! I really don't have a point to this anecdote, except how interesting it is that the purpose of the tool has changed so much.

I really like the idea of checking it with walking on the treadmill. What's funny about the HRM stuff- I remember I got my first HRM in college circa 2003ish, when I was taking running as a fitness elective- it came with the tuition for the class. The purpose of it was to work on zone training, learn about VO2max, etc. It had a calorie setting, but the teacher/coach told us to use it to gauge performance only- as in, the gross number doesn't mean anything. So I've used it for years that way. Then I got to MFP and saw 8 million posts about using HRMs, and I remember one of my first posts was asking if everyone was using zone training, and how they could possibly be using it for DVDs and whatnot- was I ever surprised to find out the HRM had become exclusively a calorie counter! I really don't have a point to this anecdote, except how interesting it is that the purpose of the tool has changed so much.

So true, and the HRM companies have complied by making it a primary focus and leaving out other useful stuff. So the cheaper Polars have no zone alarms, except an upper one. No multiple zones, missing a bunch of other features that the chipset can probably do, but is disabled.

LOL, well in doing so they have definitely exploded their target market- too bad if they leave behind the people who wanted it for it's intended purpose, I guess.

Its the blind faith issue that drives me nuts as well. The fact that these, and other devices, are not accurate is no secret, and has been stated many many times, even on this forum, but people believe what they want to believe. I see people posting over and over that hrm readings inflate calorie burn for strength training, and studies that support that fact, but also see post after post telling others to wear a hrm during strength training to know your calorie burn.

Hrm's are designed to do one thing, tell you your heart rate. The calorie burn function is best described as "for entertainment purposes only". Don't know about others, but I find people using the readings so literally, and making sure they eat those numbers back, to be VERY entertaining sometimes.

Its the blind faith issue that drives me nuts as well. The fact that these, and other devices, are not accurate is no secret, and has been stated many many times, even on this forum, but people believe what they want to believe. I see people posting over and over that hrm readings inflate calorie burn for strength training, and studies that support that fact, but also see post after post telling others to wear a hrm during strength training to know your calorie burn.

Hrm's are designed to do one thing, tell you your heart rate. The calorie burn function is best described as "for entertainment purposes only". Don't know about others, but I find people using the readings so literally, and making sure they eat those numbers back, to be VERY entertaining sometimes.

Well, the studies have shown they can get closer than probably just to entertain or curiosity aspect.
The Firstbeat algorithm HRM's have shown really good accuracy over course of a day in a study, if within 10% is good anyway of metabolic chamber.

But still again, that all applies on other stats being entered correctly on it, or the assumptions the HRM must be making if it's a stat you can't enter.

And correct usage as you indicate, most are designed with steady-state aerobic, anything outside that, even with correct stats entered, is going to lose accuracy, like weight lifting you mentioned. Or HIIT that is popular.
You look at the studies on the benefits of HIIT for fat burning say, and the energy expended is 1/2 or less what the aerobic endurance group did per hr, and you realize that the logged 900-1000 cal burns doing HIIT are no where near accurate.
Of course, that implies the HIIT is being done correctly too.

Practically, how many HRMs use Firstbeat technology? And how many actually use R-R analysis? (which I think you need in order to get the full benefit of the FB software, although I could be wrong). For example, you have to go all the way up to a Polar RX800 (RS800?) or Suunto T6d to get the full R-R analysis feature and now you are over $400 for the HRM. I asked some of these questions to people at First Beat, but never got a real answer (I got answers, but, even in English they didn't make any sense ;-). And I could never bring myself to drop the $$ on one for myself to try it out.

Practically, how many HRMs use Firstbeat technology? And how many actually use R-R analysis? (which I think you need in order to get the full benefit of the FB software, although I could be wrong). For example, you have to go all the way up to a Polar RX800 (RS800?) or Suunto T6d to get the full R-R analysis feature and now you are over $400 for the HRM. I asked some of these questions to people at First Beat, but never got a real answer (I got answers, but, even in English they didn't make any sense ;-). And I could never bring myself to drop the $$ on one for myself to try it out.

Excellent point.

Even the Garmin's are up there in price, but not that bad though, wow. I knew Suunto always seemed overpriced to me, and the nicer Polar's, but wow. And I've noticed some of the Suunto's use the Firstbeat training stuff, not calorie burn stuff.

But probably when you are getting that nice of a HRM, that is indeed for training and logging and ease of doing intervals because of correct timers, easier to use zone control, ect. Now at that level, calories is probably a side stat, interesting, but the athlete knows how much they need to eat to keep performing.

I have been very impressed with the Garmin 310XT. I'll do extra laps so a segment has stats on it's own, just for comparison.

I've noticed that the first 5-10 min has higher cal/min during that warmup, compared to cooldown last 5-10 min at a higher HR actually. And any laps at harder effort, even with same or higher HR, start showing less and less cal/min.
I've noticed that at the exact same HR, a hot day has less cal/min, because of heat elevated HR, but effort isn't really that hard.
I've noticed that a low HR cardio activity the day after weight lifting of same muscles, gets higher cal/min than same low HR day after an aerobic day. Harder to use the sore muscles, more effort even though HR doesn't reflect that fact.
On HIIT activity, despite the high HR, I show the smaller cal/min as expected, and depending on how fast I let the HR drop to recovery.

Found it very cool.

In fact you can do a Leaf test to put your stats on there as to how many calories burned for HR ranges, but I think that would actually be less accurate.
I do wish though I could put in my own tested VO2max rather than it using the formula and data logging to calculate what it must be. It's probably semi-close, but since it's based on BMI rather than bodyfat%, I know it's off.
I'm planning on making a spreadsheet with what the Leaf test would do anyway, test some sample data and see where it's at.

You'll appreciate this. When I was out of work in 2009, I seriously considered purchasing a New Leaf system and starting up a business as an itinerant metabolic tester ("VO2 max! Get yer VO2max right here!"). Mrs Azdak was concerned--and rightfully so--that I would spend all my time using it on myself for various experiments ("You are NOT bringing that thing in the bedroom!").

I passed at the time, but it's still something I would like to do.

^I'm enjoying watching my 2 buddies chat and picturing one of them running down the street with a battery.

My Polar RCX5 lets me modify my VO2 max range.... But I am too lazy to adjust it.... I just recently figured out how to add " another sport" to log my bootcamp calories burned.

For the majority of my weight loss I logged the calories that the Precor treadmills were telling me I burned. I diligently entered my weight each time as that is a crucial factor in the calculation. I used the Precor estimates because they seemed reasonable and the treadmill actually knows exactly what you are doing and almost every factor involved (weight, speed, incline). I've always tried to educate folks who automatically assume that the gym machines are inaccurate. It depends on brand and especially depends on whether you provide your weight. My weight loss was dead on during this period, so my TDEE must not have been too far off MFP's BMR + entered exercise calories.

Interestingly, I acquired a new HRM during this process (a FT7, I didn't really need the additional features of the nicer ones) and began to compare my HRM's calorie calculation to the Precor. At first, my heart rate monitor indicated that I burned more calories than the treadmill. However, I was getting fitter over time and my heart/lung capacity was rapidly improving. Eventually, the HRM and Precor started coinciding and later the HRM started recording less calories than the Precor. Now, I understand that as you become more adept at an exercise your new efficiency is going to lead to a lower energy expenditure, but I have hard time believing that it would make that much difference to a non-elite athlete such as myself. I think as you get more fit the HRMs accuracy goes down to some extent. My guess is that the formulas it uses is based on some average person (a Finnish person maybe). As you become less average and more "elite" you start to fall out of the norm. The reverse is true as well, I suspect. If your heart and lungs are way below average you will show a much higher burn even though you may not be expending any more energy.

In any event, I switched to actual biking as my main exercise in May and thus have to rely on the heart rate monitor for calorie burns. I do wish apps such as Endomondo which I use for exercise tracking were smart enough to do really accurate calorie calculations. After all, it knows the time, your weight, your speed, and the elevation you gained. The only things it can't account for is weather, though by plugging into available weather data it could potentially account for things like headwind etc. Instead, it uses some generic formula which seems to inflate calories burned by about 20%. When I enter my polar average and max heart rates it recalculates the calories burned and comes awful close to the Polar calculation, which means that they likely use the same formula.

At the end of the day, everything is an estimate. People need to be observant of how the numbers they entered are calculated and adjust accordingly.

eg
For the majority of my weight loss I logged the calories that the Precor treadmills were telling me I burned. I diligently entered my weight each time as that is a crucial factor in the calculation. I used the Precor estimates because they seemed reasonable and the treadmill actually knows exactly what you are doing and almost every factor involved (weight, speed, incline). I've always tried to educate folks who automatically assume that the gym machines are inaccurate. It depends on brand and especially depends on whether you provide your weight. My weight loss was dead on during this period, so my TDEE must not have been too far off MFP's BMR + entered exercise calories.

Interestingly, I acquired a new HRM during this process (a FT7, I didn't really need the additional features of the nicer ones) and began to compare my HRM's calorie calculation to the Precor. At first, my heart rate monitor indicated that I burned more calories than the treadmill. However, I was getting fitter over time and my heart/lung capacity was rapidly improving. Eventually, the HRM and Precor started coinciding and later the HRM started recording less calories than the Precor. Now, I understand that as you become more adept at an exercise your new efficiency is going to lead to a lower energy expenditure, but I have hard time believing that it would make that much difference to a non-elite athlete such as myself. I think as you get more fit the HRMs accuracy goes down to some extent. My guess is that the formulas it uses is based on some average person (a Finnish person maybe). As you become less average and more "elite" you start to fall out of the norm. The reverse is true as well, I suspect. If your heart and lungs are way below average you will show a much higher burn even though you may not be expending any more energy.

In any event, I switched to actual biking as my main exercise in May and thus have to rely on the heart rate monitor for calorie burns. I do wish apps such as Endomondo which I use for exercise tracking were smart enough to do really accurate calorie calculations. After all, it knows the time, your weight, your speed, and the elevation you gained. The only things it can't account for is weather, though by plugging into available weather data it could potentially account for things like headwind etc. Instead, it uses some generic formula which seems to inflate calories burned by about 20%. When I enter my polar average and max heart rates it recalculates the calories burned and comes awful close to the Polar calculation, which means that they likely use the same formula.

At the end of the day, everything is an estimate. People need to be observant of how the numbers they entered are calculated and adjust accordingly.

The reason your HRM became out of sync over time is because the settings became outdated as your fitness level improved. People mistakenly believe that you "burn fewer calories as you become more fit". That is usually not the case. It's just the HRM becomes less accurate because it doesnt know your new fitness level.

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