How does Garmin compute your Vo2max and how to increase this value

How does Garmin estimate your Vo2max
How to make this estimated Vo2max higher?
In this video we explain the factors that get into the computation and how one can influence them.
We also discuss how some training zones could potentially get the estimate downwards

00:00 Intro
00:30 How does Garmin estimate the Vo2max
00:54 The 2 main factors that can change the Vo2max
01:47 Different intensity zones impact the Vo2max differently
03:18 Why are lower intensity zones less "efficient"?
03:38 Possible explanation 1: running economy
04:18 Possible explanation 2: fat uses 12% more oxygen than carbs
05:16 Appendix 1: detailed Vo2max estimation steps
05:41 Appendix 2: maths behind the fat/carb oxidation

Sources:

FirstBeat patent:
https://patentimages.storage.googleap...

Glucose oxidation:
https://www.ncbi.nlm.nih.gov/books/NB...

Fat oxidation:
https://chem.libretexts.org/Courses/B...

ml of oxygen per mol:
https://planetcalc.com/7916/

Energy used when running a mile:
https://pubmed.ncbi.nlm.nih.gov/20613650