Polar HRM calorie burn estimate accuracy - study
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^I'm enjoying watching my 2 buddies chat and picturing one of them running down the street with a battery.
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Just in my experience, my heart rate monitor gives MUCH higher readings that my BodyMedia. I have both a Polar FT4 and a BodyMedia Fit. I use the HRM very infrequently - I don't trust it at all.
For example, we went on a tough hike last Thursday. Just for kicks, I wore both my BodyMedia and my Polar FT4. The Polar said I burned 1829 calories and the BodyMedia said I burned 889.
Here are a few other examples of the discrepancy between the two devices:
65 minutes of circuit training
Body Media Fit: 284 calories
Polar FT4 Heart Rate Monitor: 537 calories
65 minutes of circuit training
Body Media Fit: 284 calories
Polar FT4 Heart Rate Monitor: 537 calories
35 minutes of step aerobics and 30 minutes hiking
Body Media Fit: 439 calories
Polar FT4 Heart Rate Monitor: 738 calories
60 minutes of cardio drills
Body Media Fit: 361 calories
Polar FT4 Heart Rate Monitor: 627 calories
I stopped using my HRM regularly a couple months ago and have been using the BodyMedia to determine my TDEE. It's been very effective. I finally feel like I'm not struggling to accurately figure my maintenance calories.
Using the BodyMedia, I've stayed a 137 pounds (female, 5'9", 20%bf) for six weeks now - which is exactly where I want to be!
This is similar to what I"ve been doing with my F11 - tonight, with a combo of running on treadmill for 20 minutes, followed by an intense workout with my trainer to another 25 on the treadmill, my Body Media Fit was approximately 550, while my HRM was 932. I logged the lower of the two. It also has me regularly running with a heartrate of 170ish, and while I'm sweating, I can still talk. Any advice? It's an old HRM, but it's Polar. Generally a good brand.0 -
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.0
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This is similar to what I"ve been doing with my F11 - tonight, with a combo of running on treadmill for 20 minutes, followed by an intense workout with my trainer to another 25 on the treadmill, my Body Media Fit was approximately 550, while my HRM was 932. I logged the lower of the two. It also has me regularly running with a heartrate of 170ish, and while I'm sweating, I can still talk. Any advice? It's an old HRM, but it's Polar. Generally a good brand.
If you are in the 170's talking, and if you look in the HRM personal stats and it says your HRmax is 174 (220-age) - then you are getting greatly inflated calorie burn estimates.
I'd suggest thinking about what is the highest HR you ever saw, when you really pushed yourself so hard you had to stop to recover, and add 5 to that number as your HRmax.
Don't go off what may have been an inaccurate blip in the post-workout stats, but what you saw getting there and dropping back down.
Or measure yourself - sounds like you may be up for some pain, I mean fun.
http://www.myfitnesspal.com/topics/show/466973-i-want-to-test-for-my-max-heart-rate-vo2-max
If that model does VO2max stat too, here ya go to correct that one also.
http://www.myfitnesspal.com/topics/show/577839-hrm-s-with-vo2max-stat-improve-calorie-estimate0 -
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.0 -
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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.0 -
Ditto to this statement! and to add I already knew that there is no HRM 100% accurate. Just like calories in and out are not 100%.. These are good guages for us to go by and close enough to work if we are trying to lose weight. When we plautue than we should tweak things a bit.Personally I don't care if mine is off, just having one in itself, seeing the results makes me WANT to workout more. It makes me want to get more exercise in to see the numbers go up. Ever since I got it I've been in love with it :P Interesting study I guess, mine's an FT60 so I would assume it's a least a little more accurate either way I'm happy, was $130 or whatever it cost well spent imo
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I have a Polar F7 and have been using it regularily during my workouts. It always shows more calories burned than my fitbit which i wear daily under my clothing.
So now you are saying that my Polar is lying to me?0 -
I have a Polar F7 and have been using it regularily during my workouts. It always shows more calories burned than my fitbit which i wear daily under my clothing.
So now you are saying that my Polar is lying to me?
I don't know how seriously you are using the term "lying", but that's not what is going on.
HRMs are set up to estimate calories expended under certain exercise conditions. Their accuracy depends on:
1. How closely the exercise you are doing matches the assumptions behind the HRM calorie-estimating formula.
2. The accuracy/quality of the calorie-estimating formula itself (not all HRMs are the same--these formulae are proprietary products; this is why people feel that the Polar-brand products are the best--they have better equations than other brands, as do Suunto and some Garmin products).
3. The accuracy of the setup information--that means, as closely as possible, having actual HRmax and VO2max values.
HRMs calorie estimations are given an importance that is vastly disproportionate to their actual value. Why is this?
1. The human capacity for self-BS is unlimited. People WANT to believe in these devices so much.
2. The manufacturers play a kind of shell game with these devices. They don't really claim that they are super accurate, but they imply it with their marketing. It's a classic case of lying by only telling part of the truth. It is instructive to note that, while the calorie-counting feature is probably the #1 reason why the casual exerciser buys an HRM, there is little or no documentation in the user manuals about the feature. You get pages and pages of information on zone training and HR programs, but zippo on the calories or how to make that reading more accurate. Why? Because they know.
3. The other sources of information--many (not all) exercise machines and data tables--are even more inaccurate much of the time.
4. Many fitness people have a fairly shallow understanding of exercise physiology. Since they can't tell the difference themselves, they all too willingly buy into unsupported fitness hype and spread the misinformation themselves.
That being said, the Polar is likely to be more accurate for exercise calories that a fitbit. My experience with a body bugg (which I think is more accurate than a fitbit) is that it was not of much use for estimating exercise calories.0 -
Probably a great tool if the user is aware of its limitations. And I'm sure it can be a huge motivator to see the impact exercise has on fat burn. When I was trying to lose weight, I always tried to run on days that I knew I'd go over my allotted calories. Seeing results from an HRM is confirmation that exercise is an important tool in your weight loss arsenal, and it's impact can be quantified.
Having said that, I never used an HRM. I used calorie burn approximations found on this site. However, I always entered it in conservatively. So a 30 minute jog became a 20 minute jog, etc., etc. I think a similar approach should be employed with HRM readings. Take 75% of the total before entering it. Especially if you're struggling to lose weight and you appear to be meeting your daily net (after exercise) calorie goals, with no results. Overestimating calorie loss from exercising could be a bit part of why you aren't losing weight.
Another cause for overestimation: even if you were sitting on the couch watching TV, you would still be burning calories. And those calories burned by doing next to nothing are already included in MFP net totals. Which is why nobody enters (I hope) "Watching TV for 2 hours: 120 calories burned." So you should subtract what you would have burned doing next to nothing from the total calories you burned by jogging, or whatever other exercise you performed.
--P0 -
Another cause for overestimation: even if you were sitting on the couch watching TV, you would still be burning calories. And those calories burned by doing next to nothing are already included in MFP net totals. Which is why nobody enters (I hope) "Watching TV for 2 hours: 120 calories burned." So you should subtract what you would have burned doing next to nothing from the total calories you burned by jogging, or whatever other exercise you performed.
Oh great, I sense another thread starting with arguments, since the cleaning one always does.
I logged standing up eating over the kitchen sink, or cooking, or shower time, can I eat those calories back?
That would be great to see - watched marathon set of Biggest Loser for 8 hrs - 600 calories. How many should I eat back? Well, I actually watched while eating potato chips.
LOL.0 -
My head hurts!
This ^^
... too... many...words.... and ...numbers..
*falls over*0 -
I have a Polar F7 and have been using it regularily during my workouts. It always shows more calories burned than my fitbit which i wear daily under my clothing.
So now you are saying that my Polar is lying to me?
I don't know how seriously you are using the term "lying", but that's not what is going on.
HRMs are set up to estimate calories expended under certain exercise conditions. Their accuracy depends on:
1. How closely the exercise you are doing matches the assumptions behind the HRM calorie-estimating formula.
2. The accuracy/quality of the calorie-estimating formula itself (not all HRMs are the same--these formulae are proprietary products; this is why people feel that the Polar-brand products are the best--they have better equations than other brands, as do Suunto and some Garmin products).
3. The accuracy of the setup information--that means, as closely as possible, having actual HRmax and VO2max values.
HRMs calorie estimations are given an importance that is vastly disproportionate to their actual value. Why is this?
1. The human capacity for self-BS is unlimited. People WANT to believe in these devices so much.
2. The manufacturers play a kind of shell game with these devices. They don't really claim that they are super accurate, but they imply it with their marketing. It's a classic case of lying by only telling part of the truth. It is instructive to note that, while the calorie-counting feature is probably the #1 reason why the casual exerciser buys an HRM, there is little or no documentation in the user manuals about the feature. You get pages and pages of information on zone training and HR programs, but zippo on the calories or how to make that reading more accurate. Why? Because they know.
3. The other sources of information--many (not all) exercise machines and data tables--are even more inaccurate much of the time.
4. Many fitness people have a fairly shallow understanding of exercise physiology. Since they can't tell the difference themselves, they all too willingly buy into unsupported fitness hype and spread the misinformation themselves.
That being said, the Polar is likely to be more accurate for exercise calories that a fitbit. My experience with a body bugg (which I think is more accurate than a fitbit) is that it was not of much use for estimating exercise calories.
This should be required reading for anyone wishing to purchase a HRM. Excellent post!0 -
Thought I might piggyback here and see if anyone could help me figure things out.
I had my thyroid gland removed last June. While my recovery from the surgery was swift, I’ve experienced a few physiological changes I’m not thrilled with. Specifically, I have a lower resting heart rate and a lower max heart rate. My resting went from the 70s to the 50s. And where I once successfully maintained an average HR in the 140s and 150s while jogging for instance, it seems now that I’m gasping for air when it’s in the 120s. It’s very hard to get it up high. Does that mean that I am burning fewer calories now doing the same exercise I was doing prior to the thyroidectomy?
I had my RMR tested at a university in May. It came back at 1699. Not bad at all. The nutritionist told me that was slightly less than average for a woman my age and body composition. Yet, regardless of breaking even on cals in v cals out (at least according to BodyMedia—which I’ve since ditched—and Fitbit—which I still wear), I can’t even maintain my weight and have packed on 20 pounds in the last year. All of which is a bit disheartening since at one time I could say I’d lost over 130 pounds and kept it off while averaging around 2200 cals in. I’m having a hard time finding the magic number. I’ve crunched numbers using spreadsheets I’ve found here on MFP and everything keeps pointing to something around 2100. But I fear that may not be work because my HR is lower than “normal.” Despite my endocrinologist trying to tell me my new low resting HR meant I was athletically adept. I’m no Lance Armstrong!
I’ve also had a “cardio coach” session where my VO2Max was determined at different heart rates. So I’ve been using a formula where I plug in my VO2Max number based on my avg HR for that session to figure out calories burned. Is this my best bet for determining cals burned? The numbers are much higher than Fitbit and about 100 or so more than my Polar F7.
PS. I’m a 50 yr old female, 5’10” and currently 235 pounds. And yes, menopause already has one foot in the door! Yet another factor in my poopy sitch.
Any knowledgeable advice is welcome. Thanks in advance.
-Cynthia0 -
Thought I might piggyback here and see if anyone could help me figure things out.
I had my thyroid gland removed last June. While my recovery from the surgery was swift, I’ve experienced a few physiological changes I’m not thrilled with. Specifically, I have a lower resting heart rate and a lower max heart rate. My resting went from the 70s to the 50s. And where I once successfully maintained an average HR in the 140s and 150s while jogging for instance, it seems now that I’m gasping for air when it’s in the 120s. It’s very hard to get it up high. Does that mean that I am burning fewer calories now doing the same exercise I was doing prior to the thyroidectomy?
I had my RMR tested at a university in May. It came back at 1699. Not bad at all. The nutritionist told me that was slightly less than average for a woman my age and body composition. Yet, regardless of breaking even on cals in v cals out (at least according to BodyMedia—which I’ve since ditched—and Fitbit—which I still wear), I can’t even maintain my weight and have packed on 20 pounds in the last year. All of which is a bit disheartening since at one time I could say I’d lost over 130 pounds and kept it off while averaging around 2200 cals in. I’m having a hard time finding the magic number. I’ve crunched numbers using spreadsheets I’ve found here on MFP and everything keeps pointing to something around 2100. But I fear that may not be work because my HR is lower than “normal.” Despite my endocrinologist trying to tell me my new low resting HR meant I was athletically adept. I’m no Lance Armstrong!
I’ve also had a “cardio coach” session where my VO2Max was determined at different heart rates. So I’ve been using a formula where I plug in my VO2Max number based on my avg HR for that session to figure out calories burned. Is this my best bet for determining cals burned? The numbers are much higher than Fitbit and about 100 or so more than my Polar F7.
PS. I’m a 50 yr old female, 5’10” and currently 235 pounds. And yes, menopause already has one foot in the door! Yet another factor in my poopy sitch.
Never heard the medical term "poopy sitch"! Ha. Glad you made it out of the surgery and kept going.
You can lose cardiorespiratory fitness, if you mean this last past June, and recent observation. If you mean last year, and you've as a good as normal routine, then that is a change.
Now, the surgery may have just kicked off early and suddenly a change that was going to happen anyway, the shock to the system. My metabolism really seemed to change after a shoulder surgery in early 20's, Dr said that wasn't unusual, and I may or may not get back to previous. Lovely. Hair started falling out early too, though that was going to happen eventually too.
You may be burning fewer calories at rest and sleep, but activity the only lowering would be from being more fit, so slight decrease there. But really, it takes so much energy to move so much mass in certain ways, where your HR is just means you burned certain ratio carbs:fat, and how fit you are.
If you are gasping for air, it's just as hard an effort. Just confirm you lower the HRM stat for HRmax so you have an idea where you are. Just means you have a lower range, that's all.
That formula using VO2max is going to be pretty good, it's based on a study paid for by Polar after all. And they will be higher than FitBit and even Polar, which has to estimate what your VO2max may be to use similar formula.
http://www.braydenwm.com/calburn.htm
And here is a spreadsheet where you can put in your stats, AND your tested RMR, and base info on that. And with calculated workout calories, even figure out your better TDEE estimate based on that, to take a deficit to. Don't slow down that high RMR.
And HRM tab to see if your VO2max is better or worse than calculated.
http://www.myfitnesspal.com/topics/show/717858-spreadsheet-bmr-tdee-and-deficit-calcs-macros-hrm
Oh yeah, the FitBit and BodyMedia, are basing the foundation of their estimates on age, weight, height BMR, and from your RMR you are about 220 below that. So they would be overestimating daily activity which they can at least be more accurate with, but in that case may actually be right for real exercise.0 -
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When I first got my HRM, I didn't know much about them, other than reading this forums gave me the idea that they are more accurate than other methods of determining calorie burn. I remember reading something about VO2 max but since I didn't understand I didn't go out of my way to get a more expensive HRM (although my Polar FT7 is not cheap by my standards). I was under the impression that you could input MaxHR or VO2 Max into it but I am apparently wrong. So far it has not been a problem, luckily. The algorithm used seems to be working for me (has for ~ 6 months).
However, I did find somewhere on these forums the info that the algorithm COULD be wrong and that you can fix it by using (it was either a website or a spreadsheet) whatever this person posted to figure out what age you could input into your Polar to change the MaxHR. Unfortunately, I have no idea where that post is anymore. Between the power getting shut down with the hurricane and my husband closing my websites, it isn't open in my tabs anymore. But with a bit of searching, if you are so inclined, I'm sure one could find it and "fix" their HRM if they feel that the calorie burn is inaccurate.
Thanks everyone for the informative posts (OP and other subsequent posters who also had backed up research)!
Edit: Yay! Found the post!
http://www.myfitnesspal.com/topics/show/466973-i-want-to-test-for-my-max-heart-rate-vo2-max0 -
I'll be getting Polar FT7 in the next couple of days, so BUMP0
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