@Tieutieu you can find the chart here. Wondering if Suunto uses the same for displaying fitness level on the vertical.
https://www.suunto.com/nb-no/Support/Product-support/suunto_ambit3_sport/suunto_ambit3_sport/funksjoner/ytelseniva-av-loping/
Good point with the developing of the fitness level. After som hiking trips the Vo2 max is dropping đ
It is bin said that the calculated Vo2 max is pretty near that you are measuring at a lab test