Vo2 never changes

Is cycling all that you do? I'm asking because cycling vo2max can be assesed only when you have a cycling power meter (which the FR45 does not support anyway).

Well there's my answer, thank you and yes I don't run anymore and the only power meter I have is my (Garmin) tacx flux, it is used solely on Zwift and although it automatically transfers the files to Garmin Connect and shows my power, I think something isn't quite right in the way garmin collects and uses Zwift's data. 

'Connect' has managed to collect enough data from my Zwift session to provide a cycling power curve which is accurate but does not update my Vo2 figures. 

Vo2max is calculated by the watch, not garmin connect, so if the watch does not get power data, then it cannot calculate vo2max.

Thank you for clarifying the way the systems work, it also answers my next question, which was going to be - could I use the (Garmin) Tacx training app and my indoor bike to produce a Vo2 estimate but as it's the watch that calculates the figures then I'm snookered again, Thank you for your help. 

Can I ask another question? Does your Zwift show your heart rate from your FR45-watch?

I seem to remember trying the heartrate broadcast function but couldn't get it to work with my tacx flux and Zwift (this may have been a Bluetooth issue) so I use a wahoo tickr chest strap, also I've got so frustrated with the watch I sold it on ebay and bought the fitbit charge 5, which appears to have a more accurate heart rate function and I'm very happy with it, sorry Garmin didn't work out for me, maybe they could produce a more cycling focused watch in the future, fingers crossed. 

merci je viens d'avoir ma réponse grace a vous . ma vo2max est a 41 alors que la vo2max cyclisme est a zero