VO2Max dropped after watch change

Same here, I switched from a fenix3 to the fenix6x pro. It was 54 and is now 47. I imagine it could be due to the fact that I was using the fenix3 for running only. Now with the constant HR monitoring on all activities during the whole day it could be calculated differently. In the end I don't care too much but see it as another number challenge to increase it again :)

EDIT: In addition the fenix 6x pro recommends much longer rest phases, which I also think is because of continuous recording of activities. Right after switching it showed me up to 6 days of rest while I did not change my training behaviour. The fenix 3 was OK with just 24 to 30 hours...

jup, after my switch from the fenix 5 to fenix 6X my VO2Max dropped constantly from the first day on from 46 to 38 - at least it is back to 41 now.

also the crazy long rest phases seem strange to me. last saturday i was out biking and it wasn't really that hard, but the fenix 6 recommends 64 hours of rest!? 

for me this shows that this all are only numbers without any scientific background or use.

it was not supposed to be meaningless. I hope it's just a question of not using all available data from the past watches. (BTW, I thought that TrueUp function was there exactly to solve this problem, but apparently not)

The algorithms for calculating VO2 max on older watches were not as advanced as the algorithms on the newer watches. I'm sure it would have been more pleasing if your VO2 max went up instead of down after getting the newer algorithms, but such is life.

The more runs you do with your new watch, the more accurate the VO2 max estimate will be. More runs = more samples to calculate from.

For what it's worth, my VO2 max estimate also dropped (from 46 to 43) when I upgraded from my Vivoactive 3 to the Fenix 6. After 12 or so runs with the Fenix 6, I'm back up to 46.

In my opinion, the number itself isn't as important as seeing the long-term trends of the number. I don't care if my VO2 max is 40, or 45, or 55 - what I care about is whether it's going up or down over time.

Hello , it seems reasonable for me, and I am glad if this is an improvement.

although, based on the same data (directly imported by the tool from farming connect) , the runalyze app got a complete different (and better) result, see the picture.

I hope that eventually the results will converge 

1939505 said:

the runalyze app got a complete different (and better

Better because it's higher? Or better because you believe it to be more accurate? If you believe it to be more accurate why?

Without knowing your training schedule there's no way anyone can provide comment on why your VO2max should have dropped a couple of points.

About my training schedule, I am running about 4 times a week (around 30 to 40 km in total depending on the day), with a pace between 4:00 and 5:30 depending on the training. strength exercises (body weight), like push-ups (150 per day), sit-ups (150 per day) everyday.  besides, (but it's not accountable as I am not wearing the watch during this) basketball training 3 times a week (2 hours each) and 2 basketball games each weekend.

I and everyone I know who upgraded to a f6 series had their V•O2Max estimate reduced by about 4 points. 

The larger problem I have is the value changes by up to 10% from day to day for me and I have a friend who has it fluctuate by 15% throughout the week. Last week I had Stryd significantly increase my estimated functional threshold power and Garmin reduce my V•O2Max estimate from the same workout. Those numbers should not be moving in opposing directions. 

That all suggests to me the value is nonsense and therefore so are things like performance condition and the productive vs unproductive assessment of the current workout. 

I've concluded that the new VO2 algorithms are far, far worse than the old ones. I'm consistently between 60 and 62 on the F6, but I just ran a 2:28 marathon, and I have been wearing the watch constantly for months. When I saved the 2:28, the watch congratulated me on my newly proven ability to run a 2:53 marathon.

Mine has dropped 6 points since switching from my Vivoactive 3 at the end of December.  The more active I am, the more it seems to drop.  The number may be more accurate now but I have a hard time believing I'm in the bottom 30% for my age and gender.