Forums >Technical Support>Calorie count doesn't match what is in the tcx file
How are the calorie calculations done? Is it actually a calculation instead of reading the calories right out of the tcx file?
In this run entry it shows 1201 calories burned, but in the tcx file the calories add up to 720 which is in agreement with what is shown in GarminConnect. That is a significant difference.
When it’s all said and done, will you have said more than you’ve done?
Bonkin,
That's a good explanation!
RVDowning,
Why would you assume that Garmin's calculations are correct? The only accurate way of measuring the total caloric consumption is by going into a lab, hooking you up to a machine that measures your CO2 output. Anything short of that is an estimation and both Garmin and RunningAHEAD's values fall into this category.
Since neither values should be trusted, they are not stored. If a more accurate formula becomes available, I can change it and your data will automatically be updated. Isn't that better than a hard coded value?
From a thread on the Garmin forums we have he following quote:
"I think in general the 310XT calorie count is lower because the 310XT uses a more accurate heartbeat based algorithm for calculation than previous Garmin (& probably Polar) products. Here is a link to a Firstbeat Technologies White Paper on this subject: http://www.firstbeattechnologies.com...ure_Estimation "
The white paper is entitled "An Energy Expenditure Estimation Method Based on Heart Rate Measurement"
There is some controversy though. Many think that Garmin is underestimating. Garmin's implementation of the White Paper may be flawed.
The calculation of calorie expenditure is a physics problem: how much work is done by moving a object of a given weight a given distance. While physical fitness is part of the equation, it plays a very small role. After all, even if you're perfectly fit and are 100% efficient (i.e. does not waste any energy), you are still moving 169.5 pounds 9.37 miles.
I used the standard calorie calculation equation so I do not claim to understand it completely. However, I can't imagine that by being more fit will save you 480 calories. Also, I also don't understand how calorie consumption can be determined by heart rate either.
At least I understand why the figures are different. I have an advanced degree in math, but I'm not really interested enough to dig through the white paper. I do think that Garmin is underestimating though (on the 310XT). In the past they were accused of overestimating (305, 405, 201).. Oh, well....
Thanks for the response.
Good Bad & The Monkey
Garmin is underestimating.
I'm running somewhere tomorrow. It's going to be beautiful. I can't wait.
Poor baby
I bought a 310XT with a heart rate monitor recently and it was delivered in two parts (the HRM came the following week). I started using the watch in the first week without the HRM on a specific run and I was apparently using around 1100 calories. After I received the HRM the following week, linked it up and set it up, I did the same run and my calorie usage went down to around 750 calories??
How's that?
What activity class did you set? Also, did you indicate Lifetime Athlete? I think the higher the activity class the fewer the number of calories burned (according to Garmin). Also, I think an indication of Lifetime Athlete may lower the number. (Of course, I could have it backwards.)
If a heart rate monitor is worn, Garmin is trying to use data from it to try to give a more accurate reading. Otherwise is just uses an equation based on distance and time.