Not wearing 24/7 does this affect VO2Max?

I hadn't seen this when I was writing my last reply, but just to be clear - your VO2max shouldn't ever update based on 'all day activity tracking,' unless MAYBE during some sort of autodetected Move IQ event like a long walk or something.

Thanks for your thourough answers Herman.

It seems that some Jeremy at Garmin have been misleading me, here's a direct quote from a rather lenghty chat I had with him a month ago where I "put him against the wall" trying to get a reasonable answer to why I was suddenly seeing updates:

"Ok so I have checked with our engineers and they have confirmed your device [Fenix 5 Plus] has the ability to adjust the VO2 max on non GPS activities as well as when walking during normal daily routines without being in activity mode"

I guess this could mean MoveIQ events. And that worries me, cause that would mean that as long as there's no GPS runs, walking the dog (start-stop-start-stop-repeat) could be of equal value as numerous treadmill runs with chest strap and stryd. Where's the logic in that?
As I've said on previous similar discussions; I wish Garmin would give us the choice per activity to define for ourselves which activities should update the fitness estimates, and which should be discarded.

Furthermore, what I don't understand is once a VO2max value is registered, is the device able to differentiate between "good" and "bad" quality values as input to Fitness/TS ?

Thank you HermanB for your thorough answers. Very useful.

No problem. I'm happy to sort these confusing things out - since it's a big time saver in the long run and I get to learn how folks make sense of things along the way.

I just had a call with our development team leader who works with Garmin and asked what was going on here.

The information you got from Jeremy is absolutely correct, however, just because your Fenix 5 plus can calculate your VO2max based on accelerometer and heart rate data in the same way that, say the vívosmart 3 does. And, it can automatically recognize walking activities, so you don't need to necessarily start an activity for the analysis to take place. BUT, at the same time, there is a pretty complicated system of prioritization logic behind the scenes that emphasizes what it sees as the best representative estimates.

So, I think the take away here is that, yes, your Fenix 5 plus, can and does calculate your VO2max using the same combination of accelerometer+hr and analysis as the vívosmart type devices. But you only would only ever see version of the estimate in the longer absence of running+gps+hr or cycling+watts+hr activity data.

AND, i don't know, but wouldn't be surprised to learn, as you described, that the walking+accelerometer+hr version isn't fed into the Training Status analysis.

It's all still about analyzing activity data - but I guess it can be an automatically detected activity.

cool!

Just for extra information:

Yesterday I did nothing, not even walking the dog (no worries for the dog everyone, someone else did it).
The daily details shows steps, sleep, pulse and stress. Nothing else, no recorded activities, no MoveIQ events.

Still I got an update to my VO2max value.

That's wild. I can't explain that.

That's wild. I can't explain that.

Yes it is, and at the end of the day it makes the whole health/fitness monitoring and analysis part of the watch worthless to the users no matter how fancy or advanced the FirstBeat science is to begin with.

You say either GPS+HR or accelerometer+HR.. What about footpod+HR? That should be miles ahead of accelerometer+HR in terms of data quality.
I understand that the chain of logic can quickly get rather complex, but it seems to me that Garmin tends to tumble early in the chain due to these obvious mistakes.

I will try disabling MoveIQ all together to see if the updates stops, but yesterdays update indicates to me that the updates doesn't have anything to do with MoveIQ either.

I know this is a stretch SAHO, but do you have any other devices? Did you have one in the past that you sold? I have heard of people getting weird updates that weren't from their devices at all, but were somehow getting pulled on the server end from another device. Do the updates seem to track with your actual fitness, or are they pretty far off?

Thanks for the input Browner40 , and with Garmin it’s unfortunately not as far a stretch as one should believe, and actually kind of scary in a data privacy perspective.

I did have a VA3 that I sold last summer, but I did all possible precautions by deleting the device, factory reset, removing from account, unregistered from Garmin user etc.etc. The first Garmin rep I spoke with about this suggested that there could be a bug on the server side causing data to come trough still, and I was adviced to remove my Fenix from the account and do a full factory reset an re-pair it. Having no devices linked to the account should solve the issue apparently (?). I did as adviced, but the updates kept coming. Anyways - if this is the case, I find it strange that it took so long time before the data started to appear. (~6 months)
The second Garmin rep however (same as quoted above) rejected the theory and said this was impossible.

The values started off at about the same level where the «real» values left off but since then they have been sky-rocketing - however not in big leaps, always no more than one point increase each time - so I have more faith in the current values are over-estimated due to being fed with poor quality data. (MoveIQ dog walks...?)

(sorry for the VO2max spam for anyone not interested)

Update:
Yesterday I disabled MoveIQ, but today I still got a new update.
All I’ve done today is getting out og bed, took a dump, had some breakfast, and now laying on the couch watching some XC skiing on TV. Not sure which of those «activities» that convinced my Fenix to increase my VO2max from 49 to 50.

Just a thought; could changing your weight in GC trigger a change to your reported VO2max? In reality it shouldn't in itself as the metric isn't weight dependent being measured per kg, but if Garmin stores it as one 'lump' value for your whole body and then divides it by your weight to give the correct units, a change in your weight would, by definition, change the reported figures. I've no idea if this is the case or not, but it might explain why some people are seeing changes in VO2max for no apparent reason.