This discussion has been locked.

You can no longer post new replies to this discussion. If you have a question you can start a new discussion

What is synced and how does this affect calculations?

Former Member over 11 years ago

After updating from 2.80 to the 2.90 software for my FR610 my watch started calculating much higher calorie expenditure compared to identical workouts done before the upgrade.
According to Garmin support the upgrade in software did not include a change in calulation algorithm. I am trying to determine whether the watch was calculation wrong before the upgrade and is now working as it should, or if the upgrade messed up my watch.

I have done some experimentation, and noticed that for the 2-3 first workouts after doing a hard reset the watch gives me the same calorie expenditure as before the upgrade, then after that it starts increasing and ends up stabalizine at about 200-220 calories higher then to begin with.
I have also synced the .fit files with firstbeat athlete and their calorie expenditure are 150-200 lower than what my watch is calculating (about the same expenditure my watch used to have before upgrading to 2.90).

I am wondering if since the watch gives me "correct" (similar to before the upgrade, and the same as firstbeat athlete) calorie expenditure for the 2-3 first workouts after a hard reset, it could be possible that some history or profile data is synced wrong with Garmin Connect, and thus messing up my watch calculations?
As I understand the watch bases calculations on historical workouts and profile, and after a hard reset it gets this from Garmin Connect after a hard reset?

0 heybales over 11 years ago

Prior to upgrade you probably had to select your own Activity Level, how many hours in how many days for exercise.
That info was used to estimate your VO2max along with other details.
After upgrade that has been done away with, and now it just keeps track of your workouts to answer that question itself.

So right after hard-reset it has no historical data to know, so you are given VO2max on the low end, meaning that HR results is low calorie burn.
But then as it sees how much you workout, VO2max estimate goes up, meaning that same HR now results in higher calorie burn.

Unless you answer that question on upload to Firstbeat, it's using general VO2max estimate based on likely BMI like Polar does. Height and weight for BMI, age and gender for deciding where in the range that BMI fits for healthy to unhealthy, and then assuming they match up.

There is no HRM grab from Garmin Connect after a hard reset - it's empty.

This also shows why if a decent amount of your workouts are without the HRM on to know about that time, it'll have an underestimated VO2max to base calculations on for calorie burn.

See the Garmin tab in this spreadsheet for what they do, and the study it came from. And how if you know a better VO2max, you can tweak settings to get it closer to your reality.

https://docs.google.com/spreadsheet/ccc?key=0Amt7QBR9-c6MdFlRQXUtankwMGloTXZQZjJ5YS0zaXc&usp=drive_web#gid=14