Why is there a strange, varied fitness age in chart on app?

Secrycom Registered Users Posts: 33
Apprentice Traveler
edited January 24 in TomTom Sports
On the app of TomTom, my fitness age in my chart varies very strange. How is that possible?
I attached the chart.



  • tfarabaugh
    tfarabaugh Posts: 16,935
    Fitness age varies based on your level of activity, time spent in Z3 and above and the calculated VO2 Max. It will go up when you are less active or doing less intense workouts and down when you are more active. It also locks in at 20 when your VO2Max gets above 50 (bear in mind this is what the watch thinks your VO2Max is).

    I honestly don't feel you can make any judgments from what it is telling you in terms of fitness points or fitness age. It only uses runs or cycles to calculate points and while it does refine its readings over time, but it seems to be a random, capricious measure that ties to very little. It uses your calculated VO2Max (which will be wrong as no watch can compute this) to calculate points. It is not the amount of exercise that matters, it is the intensity. Unless you are in Z3 or higher for a substantial part of your workout it will not change anything. If your workouts are walks or jogs or anything that is not intense, it will have no impact on the age and points. It is based on whatever algorithm TT came up with, which is different than what Garmin uses or Strava uses, or anyone else. Ultimately, I don't expect a watch to be able to tell me how fit I am.