Please write the formula and constituents of Vo2 max and fitness age. What factors influence and how to improve these indicators. Thank you.
Garmin has written about it.
https://www.garmin.com/en-US/blog/fitness/tips-for-improving-faster/
https://assets.firstbeat.com/firstbeat/uploads/2017/06/white_paper_VO2max_30.6.2017.pdf
The fitness age is likely just a statistical value, but I haven't checked that. I see it as a gimmick of no real value for my training. I believe that it can't get any lower than 20 years old so I'm stuck there :-)