Vo2 max running

I think that Garmin and its Vo2 max is completely wrong

Out of curiosity, I uploaded my Garmin Connect data to Runalyze. The Runalyze VO2 max estimate is much different (and lower) than my Garmin VO2 max estimate. Both are trending in the same direction though (up).

I think the difference primarily stems from the fact that Runalyze factors treadmill workouts into the VO2 max calculation, while Garmin does not. This is important for me because in general my treadmill speed is significantly lower than my outdoor speed for the same effort. For instance, 7:30/mi pace on a treadmill (1% grade) is low Z4 effort for me, but outside on a relatively flat road I need to run closer to 7:00/mi to be at about the same level of effort. I also do a lot of hill interval sessions on treadmill, but ascent doesn't get exported into Runalyze for treadmill workouts. So there the VO2 max is unfairly penalized.

Also if you don't calibrate your treadmill distance (but edit it in Garmin Connect afterwards), the exported pace may be wrong if the watch detected your pace incorrectly. This is a common problem for me since I don't have a footpod, and I do so many different paces on treadmill that the watch usually gets it wrong via wrist movement detection.

If you're doing only outdoor workouts though, or your treadmill/outdoor paces are comparable, I don't see why the results should be so different between the two platforms. They should at least be both trending in the same direction.

Update: It also seems like Runalyze has differing ascent/descent numbers even for outdoor workouts with GPS. For instance, my most recent outdoor run had 538 ft/528 ft ascent/descent, but Runalyze imported it as 463 ft/456 ft.

At least on my 955 everything seems fine. Throw in a week or two of swimming or another intense activity where breathing comes at a premium and you will see your VO2 skyrocket.

When I read about other users improving their pace but their VO2 stays stable one thing comes to mind: your body adapted and improved. Whether that's through muscle gain, mobility, better form etc. has nothing to do with VO2.

VO2 is NOT a pure performance metric, so don't treat it as one. If you she'd a few kilos you will be faster - this has nothing to do with VO2.

Yes, it behaves a bit strange. I got a 1/2 marathon, at high pace/heart rate. The watch classified my run as Vo2Max. Runalyze showed a decrease of VO2Max (Vo2Max taken from file, so from Garmin itself.) I am lost here...

OK, but I set Runalize to present the Vo2Max rate from the garmin file, and not calculate it by itself. So it is strange that the watch tells me that the run was VO2Max, but the file itself says decreasing Vo2Max

I also noted that a run for vo2 makes it decreasing, while an easy run makes it increasing

Cool, I didn't know you could do that. How do you view Garmin's recorded VO2 max in Runalyze?

Add the column for VO2max (by file)

My finding is that short, faster runs increase the VO₂Max number but longer, slower runs tend to drop it.

My 3km runs tend to increase it. My 10km (or longer) runs tend to decrease it.