How one brand of HRM calculates calories

Azdak

I stole this (excuse me--RESEARCHED this) from another website. It's detailed and it might be a lot more information than you really want, but for those who are interested, it gives more detailed view of how some HRMs determine their calorie estimates.

http://www.dcrainmaker.com/2010/11/how-calorie-measurement-works-on-garmin.html

This article looks at Garmin products, and, as you can see, different methods are used for different models. It is unusual in that normally one does not get this much detail from any manufacturer. The New Leaf system mentioned is a metabolic cart that analyzes expired air to determine oxygen uptake (and thus actual calories burned).

Polar and Suunto use similar techniques, although their algorithms are proprietary. The top models (RS800x and Suunto T6c and T6d) use the R-R beat-by-beat analysis--the lower models use other algorithms.

Even if you don't understand all the details or care to study the topic in depth. it will hopefully support the idea that, as useful as HRMs can be, the calorie estimate numbers A) should be seen as only about 80% accurate under the best of circumstances; are most reliable and accurate ONLY during steady-state aerobic activities--the accuracy goes down when you start using them for circuit training, aerobic classes, etc (even though HRMs are probably STILL the most accurate method for estimating calories during those activities--it's just that even the most accurate method may not be all that accurate) and C) are not accurate at all when used for strength training, yoga, at rest, during average work or household activities, and under conditions of thermal stress.

UpToAnyCool

bump

thanks!

daybyday

Bump!! Might save me from buying a different one!!

binary_jester

Buffer is always good in terms of calories. I appreciate the research. Thanks.

dinos

Wow, I followed the link you mention just to read more about the HRM calorie algorithms and I'm in there for over two hours. This DC Rainmaker blog is loaded with interesting info. I added it to my favorites for future references.
Thanks for posting

IsMollyReallyHungry

bump! Thanks!

slieber

Question then: The various sites that are for fitness give between 300 and 350 for an hour-long dance class, and includes ballet in their repertoire of dance classes.

My HRM gives me more or less the same for an hour-long, goodly-paced class. Does that mean the sites that have the general estimates are just as accurate as the HRM?

The elliptical calculations for the sites are way higher than my HRM gives me (as are the actual machine calculations) for the same amount of time.

I just bought a new Polar FT40 (because my F6 was dying...). I'm still trying to work it out and figure if it's at least as accurate as the F6 was....is it?

themyriadthings

Very informative - thank you!

Azdak

Question then: The various sites that are for fitness give between 300 and 350 for an hour-long dance class, and includes ballet in their repertoire of dance classes.

My HRM gives me more or less the same for an hour-long, goodly-paced class. Does that mean the sites that have the general estimates are just as accurate as the HRM?

The elliptical calculations for the sites are way higher than my HRM gives me (as are the actual machine calculations) for the same amount of time.

I just bought a new Polar FT40 (because my F6 was dying...). I'm still trying to work it out and figure if it's at least as accurate as the F6 was....is it?

The more variable the activity, the less accurate any table or chart estimate is going to be--regardless of the source. This is one case where the phrase "it makes sense" is actually applicable. The structure of any aerobics class and the individual response will be quite variable and thus produce a large range of possible caloric expenditures. For these activities, HRMs--despite their limitations--might be the best estimate you can get. I would always be conservative about "counting" calories burned during an exercise class--the highest "calories per hour" number I would consider would be 7 times your body weight in Kilograms.

Ellipticals: there is no standard movement design for elliptical trainers and so it is impossible for any "table" -on MFP or elsewhere--to be any more than a guess when it comes to estimating calories. Only one manufacturer I know of (Life Fitness) actually tests their machine designs to develop accurate calorie equations that fit their machines--and even then they only started doing it on their later models (elevation series). Everyone else either uses old data, unrelated data, or just makes up a number for their elliptical trainers. This is another case where an HRM--despite its limitations--is probably the best choice.

Polar F4 vs F6. Given that the F6 allows you to manually enter your VO2 max and the F4 does not, I can't see how the F4 (or FT7 or FT80 ) is as accurate as the F6, but I don't know all the details of how Polar designs their HRMs.

slieber

THanks for that info Azdak. Pulled out my calculator and did that 7x calculation and found that the HRM reading is pretty accurate for the ballet class.

I have a Polar FT40, not F4. It seems to be more precise in determining the "fat-burn" zone v. the "fitness" zone (not that I care about that, actually) but not sure about the rest. The calorie count on it appears to be similar to the F6's so I would guess it's at least as accurate as that.

Thanks again so much for your help! :-)

agdeierl

I stole this (excuse me--RESEARCHED this) from another website. It's detailed and it might be a lot more information than you really want, but for those who are interested, it gives more detailed view of how some HRMs determine their calorie estimates.

http://www.dcrainmaker.com/2010/11/how-calorie-measurement-works-on-garmin.html

This article looks at Garmin products, and, as you can see, different methods are used for different models. It is unusual in that normally one does not get this much detail from any manufacturer. The New Leaf system mentioned is a metabolic cart that analyzes expired air to determine oxygen uptake (and thus actual calories burned).

Polar and Suunto use similar techniques, although their algorithms are proprietary. The top models (RS800x and Suunto T6c and T6d) use the R-R beat-by-beat analysis--the lower models use other algorithms.

Even if you don't understand all the details or care to study the topic in depth. it will hopefully support the idea that, as useful as HRMs can be, the calorie estimate numbers A) should be seen as only about 80% accurate under the best of circumstances; are most reliable and accurate ONLY during steady-state aerobic activities--the accuracy goes down when you start using them for circuit training, aerobic classes, etc (even though HRMs are probably STILL the most accurate method for estimating calories during those activities--it's just that even the most accurate method may not be all that accurate) and C) are not accurate at all when used for strength training, yoga, at rest, during average work or household activities, and under conditions of thermal stress.

I appreciate your research. To me, it seems very obvious that you would not use an HRM to calculate calories burned during your typical yoga class or during normal daily activities. However, I attend a 90-minute Vinyasa flow yoga which is QUITE different from the hatha yoga style you seem to be referring to here (and also the one that MFP includes in its database). It is highly aerobic for yoga. Yes, it isn't as consistently aerobic as say running, but for yoga, it is very aerobic, and I can definitely feel my heart rate increasing and pounding. I realize that it's a different kind of HR increase (forgive the lack of scientific jargon), as it's based on pressure rather than volume (as I think you might have said in a previous post). Still, I would say that the class I go to is about 5 times harder than when I jog. My HRM says I burn about 400-500 calories in my class (I always wait to start it until after warmup and always stop it before savasana.). searching on the internet, that is also the average given for calories burned during vinyasa. I know it varies depending on many thing, but as an AVERAGE, I think it's something I can count on. I know you're just trying to make sure we are educated, but it seems very disheartening to tell us that most likely, the HRMs are not even close to accurate. If there is no way to get close to estimating calories burned, as you seem to be saying in your posts, what do you recommend doing as an alternative? If it was as simple as watching what you eat and exercising daily for everyone, then no one would need to use MFP. I would have lost weight by now if it was that easy. So assuming I have to log all this stuff, which it seems I do, and assuming none of it is accurate, then how the heck am I supposed to have any success whatsoever?