calorie count differences

[VamP]

FWIW, training with a power meter, the rule of thumb posted by Vickster matches the measured kJ data much better than most HR based estimates.

This is my experience also.

 

[ushills]

According to research the calorie count on polar units should be within 12% when a correct VO2max is inputted, this is for men, for women the units are much more inaccurate generally giving a 33% over estimate.

 

[Rob3rt]

According to research the calorie count on polar units should be within 12% when a correct VO2max is inputted, this is for men, for women the units are much more inaccurate generally giving a 33% over estimate.

12% IMO is a very large error and that is when a correct VO2 max is entered (BTW you will need to clarify the statement made in the research, are you refering to HR at VO2 max)? Given most people do not have access to a lab to test their VO2 max, they won't be entering a correct value, that is assuming the device allows you to do so, the fact is you don't enter VO2 max at all in these devices, so what can you expect from them?

Also, power at VO2 max will vary.

 

[ushills]

CROUTER, S. E., C. ALBRIGHT, and D. R. BASSETT, JR. Accuracy of Polar S410 Heart Rate Monitor to Estimate Energy Cost of Exercise. Med. Sci. Sports Exerc., Vol. 36, No. 8, pp. 1433-1439, 2004.

What they did:
First they wanted to see how accurate Polar's predicted max VO2 and max heartrate predictions are. When you're setting up your Polar HRM it will give you suggested VO2max and HRmax numbers that are based on typical values for men and women, based on your age, height, and weight. The study measured the participants max VO2 and max heartrate by putting the guinea pigs onto treadmills and drawing blood to measure lactic acid concentrations.

Once they had measured the "true" VO2 and max HR, they set each guinea pig up with two HRMs. One HRM was configured with Polar's predicted HRM/VO2max, and the other HRM was configured with the actual HRM/VO2max that they had determined in the first part. They had the guinea pigs do different activities (treadmill, stationary bike, rowing machine) at different intensity levels, and evaluated all of the data.

What they found:
For men, the predicted VO2max was pretty close to the actual measured values. The predicted calories burned during exercise was also fairly accurate. If a man uses the Polar predicted VO2max to figure calories burned it will be about 4% off. If a man sets up the Polar with an actual measured VO2max value, it will be about 2% off.

For women, the Polar HRM predicted VO2max are not as accurate. VO2max was overestimated by 10.9mL/kg x min on average. If a woman uses the Polar predicted VO2max to estimate calories burned, it will be off by 33%. If a woman sets up the Polar with an actual measured VO2max value, it will be about 12% too high.

Borrowed from another forum.

 

[uclown2002]

When you are comparing between these units, are you setting the forerunner on cycling mode? I ask because if not, comparing a running unit to a cycling unit is a mugs game!

If the manufacturer has any sense, they will realise that the calorific burn rates vary with sport for obvious reasons. Taking into account that HR is not a particularly good metric for calculating calorie burn in the 1st place, if you then neglect to even fit your algorithm to the sport the device is to be used for, then you may as well just make a number up!

You will simply not get a true value for calorie burn outside of a lab, accepting that any values are a fairly inaccurate estimate is a healthy idea!

FWIW, training with a power meter, the rule of thumb posted by Vickster matches the measured kJ data much better than most HR based estimates.

Yes good point! I'll check but not sure I've chosen bike mode as I do other stuff. I think perhaps I've used a 'general' option.

 

[Rob3rt]

CROUTER, S. E., C. ALBRIGHT, and D. R. BASSETT, JR. Accuracy of Polar S410 Heart Rate Monitor to Estimate Energy Cost of Exercise. Med. Sci. Sports Exerc., Vol. 36, No. 8, pp. 1433-1439, 2004.

What they did:
First they wanted to see how accurate Polar's predicted max VO2 and max heartrate predictions are. When you're setting up your Polar HRM it will give you suggested VO2max and HRmax numbers that are based on typical values for men and women, based on your age, height, and weight. The study measured the participants max VO2 and max heartrate by putting the guinea pigs onto treadmills and drawing blood to measure lactic acid concentrations.

Once they had measured the "true" VO2 and max HR, they set each guinea pig up with two HRMs. One HRM was configured with Polar's predicted HRM/VO2max, and the other HRM was configured with the actual HRM/VO2max that they had determined in the first part. They had the guinea pigs do different activities (treadmill, stationary bike, rowing machine) at different intensity levels, and evaluated all of the data.

What they found:
For men, the predicted VO2max was pretty close to the actual measured values. The predicted calories burned during exercise was also fairly accurate. If a man uses the Polar predicted VO2max to figure calories burned it will be about 4% off. If a man sets up the Polar with an actual measured VO2max value, it will be about 2% off.

For women, the Polar HRM predicted VO2max are not as accurate. VO2max was overestimated by 10.9mL/kg x min on average. If a woman uses the Polar predicted VO2max to estimate calories burned, it will be off by 33%. If a woman sets up the Polar with an actual measured VO2max value, it will be about 12% too high.

Borrowed from another forum.

How did they measure calories burnt? To me it sounds like they are comparing the output of a HR monitor, with and without accurate inputs. What is the benchmark?

Just had a browse of the full paper, can not see any benchmark being used (I will re-read it in full when I get chance). My 1st impression is that the study is like measuring an unknown voltage with 2 different multimeters and then declaring one of them more accurate than the other.

 

[ushills]

Full papers here.

http://www.ncbi.nlm.nih.gov/m/pubmed/15292754/

I think going back to the op, hrm monitors should give a better guess than an algorithm in an app, however all are still approximations unless you are prepared to carry around lab equipment to carry out indirect calorimetry.

Indirect calorimetry was the comparison method used to benchmark the hrm's.

http://www.unm.edu/~lkravitz/Article folder/caloricexp.html

 

[brett sleger]

Wow what a lot of replies and great info I do have a hr monitor but its the watch type where I need one hand on the face of the watch it was a cheap aldi unit. I am obese for my height according to bmi weighing 14 stone at 5ft7. Id like to get one thats compatible with either strava or endomondo!

 

[ushills]

Wow what a lot of replies and great info I do have a hr monitor but its the watch type where I need one hand on the face of the watch it was a cheap aldi unit. I am obese for my height according to bmi weighing 14 stone at 5ft7. Id like to get one thats compatible with either strava or endomondo!

If you have a suitable phone you can use a Bluetooth hr belt that you can use with either Endomondo or Strava. Polar and Wahoo are the ones that spring to mind.

 

[brett sleger]

Excellent I shall get snooping later on as I think itl help a lot with my training zones as well!