Garmin and calorie used

[Suzannewithaplan]

I'm flumoxed, how do they calculate it

I've just started using a vivosmart, previously I'd been using the forerunner 210 in conjunction with a mio link hrm to log my cardio workouts.

Today I used both...expected the calorie burn to be different but not that different

I ran/walked uphill for 80 minutes, my average heart rate was 83% of max.
Forerunner said a disappointing 435 cals:(
Vivo smart said a shocking 865 cals

Now the calculator here:
www.shapesense.com/fitness-ex...alculator.aspx
(the one where you fill in VO2 max-I estimated my VO2 max from my heart rate after a 1 mile jog based on the calculator here www.brianmac.co.uk/vo2mile.htm)

gives me a calorie burn of 737 for the same workout so it seems as if the vivo smart is the more accurate of the two.

I know these calorie consumption figures are all only estimates but is it not weird that devices from the same manufacturer would give such different readings?

Does anyone know if the two devices use different formula to calculate calorie burn?
Furthermore is that formula any more sophisticated than the one I linked to which asks for weight, age, gender and VO2 max?

yes it would!
DCR's post here is quite helpful
also if you look up his posts on the 305 you might get more info.

Right now I'm thinking my best bet to do regular Vo2 max 1 mile jog tests (easy enough on a treadmill) get the average heart rate and workout time from whatever garmin Im using and use the online calculator which factors in vo2 max.

I've also been reading up on heart rate variability monitoring, but not sure that would tell me anything I dont already know (ie when I've been overdoing it)

Turns out the 210 uses more sophisticated calorie calc method than the VS, but the VS is just so nice

interesting post on this thread-may shed some light
forums.garmin.com/showthread.php?19274-Calorie-count-WAY-off

whether the calorie calculation use heart rate to determine calories or work it out from speed and distance is critical. I have found with my Garmin on my bike that the calories are much higher when I dont use the heart rate monitor for the same journey. I have had similar experience with a wrist garmin when running. I found the link suggested above really helpful - www.dcrainmaker.com/2010/11/how-calorie-measurement-works-on-garmin.html It clears states that anything that is heart rate related will be more accurate than a speed/distance algorithm used when you don't measure the effort you make. Interestingly if you have the heart rate monitor on it makes no allowance for speed / distance just uses heart rate. I guess your own heart rate is the best measure of how much energy you are expending.

?I know all that and I posted the same DCrainmaker link at the start of the thread.

It depends on how the heart ratedata are interpreted, without knowing weight, VO2 max, max hr and resting hr it's not possible to extrapolate cal consumption accurately from the heart rate data.
VO2 max is especially important, this can be inferred from tests that are easy to do yourself but ?getting the actual figure needs quite expensive lab testing

this is definitely true, I've just done a 10 mile run without HRM and Garmin is suggesting I've burned almost 90 calories per mile! With the HRM over same or v similar course it's about 70ish per mile, with my height and age and build at a steady pace it's not likely to much higher than that.

it's fascinating but I'm happy to work on around 70cals a mile and add it to my TDEE and dutifully eat it all most of the time

It would help if Garmin allowed you to re interpret the heart rate date using a different algorithm once you upload it to garmin connect.
Apparently the first beat technology is only licensed for use with some garmins.
Anyhow, I've reverse engineered the firstbeat algorithm so as to correct the VO2 max? value in my FR 210 so should get a more accurate reading from that today.

Mitchy no, I disagree!
If you read the post on the garmin forum thread that I linked to you'll see that garmin (if using firstbeat) will underestimate VO2 max.
That means that the cal count will be too low.
For any given heart rate a person with higher VO2 max (ie a fitter person) will burn more cals than a less fit person.

Seems like garmin expects it's customers to have the VO2 max of the average sedentary person ?

You've said you have a low resting heart rate? Mine is about 46, that means for any given level of exertion/ calorie consumption our hearts will be beating more slowly than is average, so calorie consumption (because it's based on the average person) will be under estimated

sticking my fingers in my ears

I don't want to eat even more stuff at the moment

lol, ok
but you get me, yeah?

yeah yeah whatevs