VO2 Max drops after Zone 2 Ride

VO2 Max has been gradually climbing for the past month, maybe a little longer. I did a 2 hour zone 2 session yesterday and I lost a whole point on VO2 Max. I updated to 27.13 a couple of days ago, but I did not see any vo2 max updates in the change logs so maybe that is just a coincidence. How does 1 zone 2 ride lower vo2 max by an entire point? Thanks.

0 Jan_Mantau 2 days ago

Did you enter a higher body weight? That can easily lead to the shown half point lower VO2max, because that metric is per kg.

0 iJustRide 2 days ago in reply to Jan_Mantau

Great question. No, I have the same weight entered. I weigh myself at the same time each morning. The weight has been the same for a few months.

0 5155879 1 hour ago

From a physiological and algorithmic standpoint, VO2max can’t be estimated during a Zone 2 ride. We’ll probably never know why Garmin decided to run the estimation in the first place without proper data input; maybe a heart rate or power spike, maybe too much time since the last update... who knows. All we do know is: it did.

And we can't even be sure it only used data from that session. Probably not.