Activity class and effect on Calories

yes i have. there's definitely some effect. the problem i've been wrestling with for years is what to set this activity class at. i wish there was some chart that said ok if your vo2 max is 50, your activity class is x. i haven't found anything, so it's always been basically a guess for me. 

I think that, at least to some extent, the watch makes these adjustments for you based on your vo2 max, the amount of training you do, etc. Perhaps not as dramatically as adjusting your activity class manually, though. I always kind of thought the activity class setting was mostly just used when you first set up the watch and it doesn't know your fitness level or training routines yet.

I'm honestly not sure if setting a higher class makes it calculate less or more calories burned. I set mine to 5 in the beginning and haven't ever changed it.

In any case, here's what Garmin recommends for setting your activity class:

Class Breakdown

0. No Exercise
1. Light exercise once every 2 weeks for less than 15 minutes
2. Light exercise once every 2 weeks for 15 to 30 minutes
3. Light exercise once a week for around 30 minutes
4. Light exercise once a week for around 45 minutes
5. Regular training 2 to 3 times a week for a total of 45 minutes to 1 hour
6. Regular training 2 to 3 times a week for a total of 1 to 3 hours
7. Regular training 3 to 5 times a week for a total of 3 to 7 hours
8. Almost daily training for a weekly total of 7 to 10 hours
9. Daily training for a weekly total 11 to 15 hours
10. Daily training for a weekly total of more than 15 hours

Yep, that chart was the first thing I looked at. Good to have it hear for anyone else looking in. 

Glad I'm not the only one that isnt 100% sure the role of activity class and calories. 

To add, I went on my run, and comparing with my last run, of relatively same distance, relatively same effort (hr and push), my calories for the run were relatively the same (between activity class of 3 and 7).

I will see what it is for biking tonight. 

so last summer i had a polar vantage v. i wore it while using my edge 830 for mountain biking. recorded rides using both devices. it was driving me crazy that the calorie counts were so off between them (using the same HR strap). the garmin was always showing far more calories burned (like 100-200 per ride). i began experimenting with activity levels. I set my level at 7 since forever, but in this case i began to experiment by moving the setting gall the way from 0 to 10. i noticed that when i set it to 0 the garmin was showing an even higherhigher calorie burn. it was slight, but it was there. by the time i got to the 10 setting the polar had overtaken the garmin in calories burned per ride. there's something definitely there, but i don't know what it is and i don't know what to set it at. 7 "feels" about right for me. i sit on my ass all day for work but weight train 4x a week (2-3hrs) and mountain bike 3x a week (2.5-4 hrs). now, according to that chart i should be at an activity class of 10, but when you go 8 or higher it cautions you that this range is for athletes, whiich i am most certainly not. vo2 max is currently 48. so i leave it at 7, not having even the faintest idea if it is tracking accurately or not. and for the record, i have never seen garmin change my activity level for me. i set it at 7 when i get the device and it's still at 7 by the time i'm ready to upgrade to the next device

Yeah, the fact that the watch does not determine your activity level on its own, after wearing it for months on end day and night, non stop but to charge it, is utterly baffling. I am pretty much on the same boat as you, with no clue as to what to set it at. 

I believe the higher your activity is set, the less calories you would burn.  Makes sense, the fitter you are... The easier the same activity is.  Fitter person needs to work harder to get the same calorific exoeditire

AndreiDracul said:

but it is still not clear to me how it changes calories calculated. 

How? Nohow! :-)

support.garmin.com/.../

He-he, until today I thought the class has an effect on something including energy expenditure. Following the level of my weekly workout load I have been regularly chsnging it, when I had Fenix 3HR. when I owned a Fenix 5+, and also  recently when using F6X

Thanks for that link!

Funny, coming from Suunto devices that used activity class (some auto-calculated with precision to tenths), I have been adjusting this value for years and years on Garmin devices that don't use it :-)