Using HRM data to calculate calorie burning

conceptual_primate

Hi all,

I have a garmin Etrex 30 with a HRM strap. When I look at my GPX files it records my HRM data along with the usual time, distance, direction settings etc. However, the Etrex itself doesn't estimate calories burnt during a workout. At the moment I am uploading my GPX files to Strava which does estimate this, but this uses the basic GPS data to derive estimated power (using some assumptions) and then applies a seemingly simplistic algorithm to calculate calories spent. Can anyone recommend software/website which can take the GPX feed and calculate a more accurate estimate using the heart rate data as my research suggests this is the most accurate assessment available without entering the laboratory (within 10% tolerance which is perfect for me)? Any advice welcome.

Kind regards,

CP

Alex_Simmons/RST

You'll need a power meter for that level of accuracy in estimating metabolic energy output.

top_bhoy

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19724426#p19724426]Alex_Simmons/RST[/url] wrote:

You'll need a power meter for that level of accuracy in estimating metabolic energy output.

You haven't dismissed the use of HRM data so I'll assume its not completely irrelevant. Therefore, what level of accuracy could the use of HRM data achieve?
Also, for clarification, is "metabolic energy output" another way of saying 'calories expended'?

conceptual_primate

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19724426#p19724426]Alex_Simmons/RST[/url] wrote:

You'll need a power meter for that level of accuracy in estimating metabolic energy output.

Ok, just to backtrack a little, I don't have a power meter but I can live without that level of accuracy. Do you know of any site or software that can use the HRM data to calculate this information?

Thanks,
CP

Alex_Simmons/RST

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19724528#p19724528]Top_Bhoy[/url] wrote:

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19724426#p19724426]Alex_Simmons/RST[/url] wrote:

You'll need a power meter for that level of accuracy in estimating metabolic energy output.

You haven't dismissed the use of HRM data so I'll assume its not completely irrelevant. Therefore, what level of accuracy could the use of HRM data achieve?

It depends, since it effectively involves estimating energy output from a HR signal who can really know?

The OP doesn't use a power meter and does not want to visit a lab to at least attempt to provide some kind of baseline relationship between power or energy output and HR (although as we know it is often different in controlled indoor setting than when outdoors, and of course the relationship falls down the more variable the effort on a ride is, and as the effort level nears and exceeds threshold power levels).

Then the problem arises when fitness changes. A 10% change in power (energy output and metabolised) for no change in HR is pretty typical variation for someone that trains consistently and competes, let alone someone who might see bigger fitness variations because they ride less consistently through the year.

I consider most calculations of energy output from a HR signal to be not much more than light comic relief.

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19724528#p19724528]Top_Bhoy[/url] wrote:

Also, for clarification, is "metabolic energy output" another way of saying 'calories expended'?

That depends on what is meant by calories expended.

By being specific I am ensuring the not insignificant difference between mechanical and metabolic energy output is made. One can assume the reference is to metabolic, but I'd rather be sure. Even with a power meter you are looking at being in the 5-10% accuracy range for metabolic energy output estimates, better if the ride is mostly sub-maximal and you have good lab data on your gross mechanical efficiency.

Alex_Simmons/RST

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19724693#p19724693]conceptual_primate[/url] wrote:

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19724426#p19724426]Alex_Simmons/RST[/url] wrote:

You'll need a power meter for that level of accuracy in estimating metabolic energy output.

Ok, just to backtrack a little, I don't have a power meter but I can live without that level of accuracy. Do you know of any site or software that can use the HRM data to calculate this information?

Thanks,
CP

Not to your level of accuracy requirement without reference to other forms of metabolic testing.

conceptual_primate

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19724873#p19724873]Alex_Simmons/RST[/url] wrote:

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19724693#p19724693]conceptual_primate[/url] wrote:

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19724426#p19724426]Alex_Simmons/RST[/url] wrote:

You'll need a power meter for that level of accuracy in estimating metabolic energy output.

Ok, just to backtrack a little, I don't have a power meter but I can live without that level of accuracy. Do you know of any site or software that can use the HRM data to calculate this information?

Thanks,
CP

Not to your level of accuracy requirement without reference to other forms of metabolic testing.

My 10% accuracy reference was based on the below link:
http://www.dcrainmaker.com/2010/11/how-calorie-measurement-works-on-garmin.html

In reality, I am just looking for something a bit more scientific than Strava, which uses speed to estimate power and from estimated power to calories burnt. In my head HRM data should be. I am aware there may be more scientific ways to calculate these, but for my purposes this would be fine. I just need to find a piece of software / website which can parse the HRM data, if anyone can recommend any?

imposter2.0

Why the fixation with calorie 'burning'..??

conceptual_primate

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19724954#p19724954]Imposter[/url] wrote:

Why the fixation with calorie 'burning'..??

I wouldn't call it a fixation.

Alex_Simmons/RST

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19724952#p19724952]conceptual_primate[/url] wrote:

In reality, I am just looking for something a bit more scientific than Strava, which uses speed to estimate power and from estimated power to calories burnt. In my head HRM data should be. I am aware there may be more scientific ways to calculate these, but for my purposes this would be fine. I just need to find a piece of software / website which can parse the HRM data, if anyone can recommend any?

Your desired accuracy is incompatible with the technology and assumptions chosen. No software is going to overcome such deficiencies.

What is your actual goal? Why do you want to know metabolic calorie expenditure?

imposter2.0

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19725011#p19725011]conceptual_primate[/url] wrote:

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19724954#p19724954]Imposter[/url] wrote:

Why the fixation with calorie 'burning'..??

I wouldn't call it a fixation.

Whatever you want to call it - why the focus on it?

sungod

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19724952#p19724952]conceptual_primate[/url] wrote:

My 10% accuracy reference was based on the below link:
http://www.dcrainmaker.com/2010/11/how-calorie-measurement-works-on-garmin.html

In reality, I am just looking for something a bit more scientific than Strava, which uses speed to estimate power and from estimated power to calories burnt. In my head HRM data should be. I am aware there may be more scientific ways to calculate these, but for my purposes this would be fine. I just need to find a piece of software / website which can parse the HRM data, if anyone can recommend any?

more scientific?

well, for a start, that 10% claim is from a 'white paper' produced by the company that sells the algorithm, this is marketing, not peer-reviewed scientific research, and it's based on just 32 'healthy' subjects, with no detail given on if or how results vary with age, gender, weight, fitness etc.

even if it were accurate and reliable, it still won't help you because it relies on beat to beat timing data, which you do not have

science:

for an individual at a given level of exertion heart rate can vary significantly according to that individual's current health, fitness, fatigue, etc., as a result, no method based on heart rate can give consistent results, especially in the absence of regular (re)calibration using lab measurements

there is no way to do what you want that will give good results, only twaddle, flimflam, piffle and snake oil

if you want a rough guess, just use one of the umpteen online estimators, as long as it includes perceived exertion it'll be close enough, for instance...
http://www.mapmyride.com/improve/calorie_calculator/

cycleclinic

At the beginning of the year 140bpm average had me averaging 180w to 190w now the same average averages 215w or thereabouts. The calories required for both rides are quite different. If you do not have a power meter the calories consumed are simply make believe and have no accuracy to them at all. Also on day where you are fatigued heart rate for a given power output can be high. Today I am full of cold and went racing. 2 29 average had my heart rate hitting 160 for long periods. My limit is 167bpm so you can tell how that ended up. Heart rate is affected by so many things. The only thing you can use it for is for getting intervals at the right intensity for how you are feeling that day.

With my power meter if I see my heart rate elevated after warm up I don't bother with intervals other wise I train of power alone.

Use a hrm but don't try to infer things from it that it can't do.