Calories burnt

Hi,

I have no expanation, but the same question...

My Garmin data are exported to YAZIO and there activities and "normal daily steps" are stored as separate values. Of cause, I don't start an activity every time when I'm walking or hiking, but sometimes I do (often without GPS, only to see the distance and save the steps to fit file):

I also noticed that there is is big difference on days with and without activities. Any statement?

Calories burnt are not measured or detected by your Garmin watch, but calculated based on averages for different activities.

Basically, lookup tables are used for weight, type of exercise  and length. Apparently, Garmin has different lookup tables for activity "Walking" and for "Typical day without activity" so the number of calories calculated is very different.

The calories burnt shown by your watch may, but more probably won't match the actual calories you burn. 

It seems you are right.

The calories burnt are not affected even by the heart rate. I just tested that: A day with the optical heart rate sensor turned off gives the same calories count as it was on.

I thought that heart rate plays important role in calculating calories burnt.

Like you said: Garmin used the average calories burned for a person of some age, some weight, some gender and some activity class. It will look this average up in a lookup table.

Same goes for activity. Again, Garmin uses an known avarage value for someone that is performing an activity at a certain intensity level.

Calories burned is not measured but calculated. It's all based on statistics, not on actual values. 

There are no "lookup tables".  The type of activity has nothing to do with it.  It doesn't matter if you're running, cycling, kick boxing, etc..., if you do any of those activities at the same HR for the same amount of time, the calories burned will be identical.  The activity you choose is for recording data only.  If I selected the run activity and ran for 15 mins, or did jumping jacks, or rode my bike at the exact same HR and duration for all three, that run activity will show the same amount of calories burned.  The watch only knows if your running or cycling because you selected that activity.  Yes, I would have different levels of perceived rate of exertion for all three if my HR was the same because I'm using different muscles, but 350 calories burned in an hour is exactly that.  It doesn't matter what I was doing to reach that 350 calories.  

There are lookup tables, like this one:

nutristrategy.com/caloriesburned.htm

Calculating calories is all statistics. Everyone does it that way. Garmin, Suunto, Polar.

But if you believe calories are precisely calculated by your watch for your specific situation, fine with me.

Personannly I think, Elbo is right and it sounds logical - though I really don't know exactly. The problem here in this thread was NOT the difference betwen different activities, but the difference of calories burnt WITH an activity and WITHOUT any activities a day.

I think, the calories burnt without any activity aren't specified at all, and thats why the "lookup table" is something "unspecified" at a low level (probably someone only shakes hands in a certain way and the watch identifies as walking).

I think, my fenix 5S knows the steps pretty well. But everything is "statistics", that normally is good, but not for all situations...

Now, I understand, why calories are shown with different values. Thanks.

Your link proves my point. It clearly states calories burned is factored by "intensity level ".  It doesn't matter what activity profile you choose on your watch, calories burned are based your personal metrics you set and then your effort (intensity level measured by heart rate) for the duration of the activity. You are not rewarded or punished (depending on your view) calories burned based on the activity profile you selected.  A run will record the same amount of calories burned regardless if you selected the run, yoga or indoor bike profile based off your heart rate. If I were to maintain a steady HR of 145 for 20 minutes straight I would burn the same amount of calories regardless if that activity was running, hopscotch, or balancing myself upside down on my head smacking my ass to the beat of my favorite song.  

Garmin uses algorithms licensed from Firstbeat to calculate calories based on HRV and other factors, not a simple lookup table. https://www.firstbeat.com/en/consumer-feature/calories-burned/