Fitness age reported by my watch is different from that reported by web app

Mine says 20 both in the app and in the web. My real age is 49, and VO2Max is 55.

The strange thing is that it was last updated previous Monday, and I have not done any GPS running lately. On Monday, Ì had an indoor spinning session. I didn't think that could affect my VO2Max estimates? There was no power meter on the bike.

Thanks for the info. My real age is 69, VO2 Max is 38 and fitness age is 51 in the app and 48 on the web. 

I have a 3 year difference too. I noticed it first about 3 or 4 weeks ago when my fitnness age suddenly jumped from about 26 to 36 after a run. Even though my V02Max had improved by a tiny fraction ( got the exact number reported by Garmin from Runalyse ). Made me wonder if they had changed the tables they were using for lookup as well.

Thanks for confirming this bug.

PeterQuirk said:

I have reported this problem to Garmin Support, but haven't had an answer yet. I was wondering whether anyone else has noticed that the Android app and the website report different values for fitness age on the VO2 Max menu item. For a few days, my fitness age on the web was 2 years younger than on the app. Now its three years younger!

Hello! When you look at the Garmin Connect Mobile app, it will only show the VO2 max of running, cycling, or walking, depending on what activities have been recorded and then it will show the fitness age of this. In the Garmin Connect Web, it will show the average for all of these activities and the fitness age from that. There is also a different section for Running VO2 max and fitness age that is listed under Reports, Running, VO2 Max. 

I actually had a case with Garmin about this, latest Garmin connect update fixed it for me, at least two results has been the same.