Do folks think displayed VO2 max values are reasonably accurate?

It depends on a number of factors, the most important of which is your heart rate zones. Plenty of information and discussion around VO2max in the forum. Have a read through some of the threads.

(it puts me in the "top 15%", though I still consider myself just past the "beginner" stage

I think it's top 15% of general population, not only runners. My VO2max as assessed by garmin puts me in the top 5%, and I think it's quite accurate, as the race predictor is based on that, and my PBs are quite close to what the race predictor says.

https://www.runnersworld.com/gear/a2...-your-vo2-max/

Some data of ? quality* suggesting Garmin's reported MVO2 max tends to be somewhat higher than actual. Doesn't prove the point brought up in the OP, but if true would be quite believable to me, at least in terms of my own reported data.

*I don't have any knowledge that would call the data quality into question, I worded it like that only because I didn't go read the experimental description. Lack of error bars makes it hard to interpret the data as well. And at face value, it's only off 1-2 units when using a chest strap, which isn't that bad, IMO.

Since this stat is an estimation it’s best to just look at the way it trends rather whether or not it is accurate in comparison to what a lab derived test would give.

If it’s going up, you’re getting fitter. If it’s going down, you’re losing fitness.

Not so sure about it either. I ride offroad/enduro's (KTM 500EXC), I climb, I run but I get a 40% rating. I'm a pretty fit guy though...

RobKenjiwhe what do you mean a 40% rating? I've fund the VO2 to be reasonably accurate when compared to a lab test or when compared to the race time estimates but I mainly use it as a major trend marker

I mean 40ml/kg/min, the number at the bottom of the screen. Which translates to fair. I was more expecting something between good and excellent. The other thing I noticed is that this score hasn't been updated since jan 26 although I run every other day, hike in the weekend and walk 20 stories up and down daily. Everything else is updated just fine, device syncs good and all...

RobKenjiwhe not every activity type updates VO2 max when was the last outdoor run that you did with a HR monitor (not a trail run type). Also where did you get the date of last VO2 max as being 26th Jan

If I look on the android app I can see all the data points for VO2 max up to 4th Feb when my VO2 max dropped after a couple of runs in the snow and Ice. On my Connect on the PC however the last data point I have seems to be 28th Jan - so there is some disjoin (which I have not noticed before) between the two applications.

Also you say that you are disappointed with the VO2 - as I understand it the VO2 is mainly built around running (or cycling as well iff you have a power meter) so I think that if you show good performance in running terms that will give you a high VO2 Max. Does your VO2 max estimates for expected running times equate very roughly to your performance - if it does then I think the VO2 is accurate for the purpose it was designed for but it may well not reflect your VO2 for you main focus sports.

It is really bad weather here, around freezing with rain. Interesting to see that that influences vo2max as my cadence and heart rate are pretty much the same as always. I'll give it a few weeks before I look again, see what happens!

RobKenjiwhe I think for me the snow and ice influenced VO2 because I was running same distance and course with similar HR but slower due to slipping and sliding and expending more effort in the snow. All gone now and back to warmer weather with rain:( so expect my VO2 will go up again - I don't normally notice much difference with conditions. I also run all my trail runs using the RUN activity as otherwise they don't contribute to VO2 calculations.