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?

[Mitchy1nge]

yeah yeah whatevs

[Suzannewithaplan]

lol, ok
but you get me, yeah?

[Mitchy1nge]

sticking my fingers in my ears

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

[Suzannewithaplan]

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

[Suzannewithaplan]

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 ?

[Suzannewithaplan]

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.

[Mitchy1nge]

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

[Mitchy1nge]

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.

[Suzannewithaplan]

?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

[Piedpiper2]

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.

[Suzannewithaplan]

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

[Suzannewithaplan]

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

[Suzannewithaplan]

Shiny according to this thread strava dont use the data from the heart rate monitor

[Suzannewithaplan]

I have conducted my experiment, results as follows

1-highest intensity workout
vivosmart = 865 cals, forerunner 210 =435 cals (FR is 50.23% of the VS total)

2-medium intensity
VS=243 cals, FR 156 cals (FR is 64.2% of the VS total)

3-low intensity
VS=158 cals, FR= 105 cals (FR is 66.5% of the VS total)

so the relation between the totals isnt consistent, but there is a pattern.
The VS calorie burn rate increases more quickly as intensity increases.
When exercising at higher intensity there is a greater post exercise effect (as discussed in this paper www.firstbeat.com/userData/firstbeat/download/white_paper_epoc.pdf)

I know that some garmins use first beat but I don't know if the VS does, if it does then the higher intensity calorie count may be due to the device including excess post-exercise oxygen consumption in it's calculation.

I may e-mail garmin and see if they will explain

[Suzannewithaplan]

thanks Thistle! :o

[Thistledew]

I can't answer your question, but will have a play around with my Garmin gadgets and report back. I have a Garmin 800 bike computer and a new Garmin swim/bike/run gadget that I can't remember the name of as I only got it for my birthday earlier this week!

I have noticed that there is a real difference in the calorie calculation on my bike computer when I use it without the hrm as opposed to with. It increases the figure by over 50% if I use it without hrm.

I also think it under calculates calorie consumption when I run, as doing 10k in an hour usually comes back with a consumption of 500 and something. I will be interested to see if the gadget designed for running calculates differently, as opposed to the one designed for cycling.

[Suzannewithaplan]

Actually I could test that theory by using both devices to record my workouts if the relationship between the two results remains constant that would suggest that they are using the same formula but just tweaking it up or down

(will report back!)

[Suzannewithaplan]

?Seems to me that the problem is not just that they all use different formulas but that they are not open about the formulas that they use.
Getting such different results from two devices from the same manufacturer makes me suspicious of their motives, it is as if the marketing dept has decided that the consumer who buys a vivosmart is more likely to respond to the 'flattery' of a higher calorie burn, whereas the purchaser of the fore runner is more serious and realistic.

Perhaps the formula is accurate but one device upregulates and the other downregulates, in which case I just need to determine by what percentage I should shift the result?

[shinysparklythings]

This winds me up so much! I cycle rather than run and use a hrm for improved accuracy. My bryton(like a garmin different make) will say 2673 cals I upload the same data to strava and it will say 1465 cals for example!

So annoying! I guess they all use slightly different formulas. In theory it should be more accurate with a hrm but probably only if your max heart rate had been set accurately from doing a threshold test.

[Mitchy1nge]

I rarely use my HRM, is not like I understand or use the zones anyway, think last time I used it was to compare cycling rowing and running over similar distances. Running always wins, then rowing and then cycling.

Today it says I burned 730 over 8.5 miles which is pretty high at about 85 cals per mile, especially as it was at long run pace, total elevation gain was 72m, it didn't feel like a particularly undulating route but I was too scared of being run over to notice. Which is probably a good reason to use a treadmill but nah.

[Suzannewithaplan]

are either of you using a heart rate with the garmins?
the workout I mentioned was on a treadill so no gps data

[postmanpatscat]

I usually get about 340 cals for a 30 min 5k on Garmin, considerably more than I get on a treadmill or Fitbit so I go with the Garmin data since I don't track my food anyway.

[pootlebug]

I have a Garmin Forerunner 110. I have just compared calories for a couple of recent runs. Obviously had to put 0% gradient into the calculator above, whereas both were slightly undulating, but not stupidly hilly.

Half marathon:
Garmin 1,333 calories
Calculator above 1,352 calories

Parkrun:
Garmin 309 calories
Calculator above 316 calories

Maybe it's to do with how well they measure (and how accurately they calculate, based on measurements) elevation gains?