About fitness age

Mikael Kolacny
Mikael Kolacny Registered Users Posts: 1
Apprentice Seeker
edited January 24 in TomTom Sports
How come that my fitness age has changed from 20 years/measuring VO-max to 48 years old in a week in april this year? My training level is about the same as earlier. This happened at the same time when I bought a new computer, and to which I now connect my Tomtom Watch. Could this be related and why?