Real VO2 Max correspondence

Hi there. I've been tested with Ergometer Test/Aerobic Functional Capacity. I wanted to know how reliable my Fenix 5 was. I?m a little bit disappointed because the value given by the Fenix was (?very?) different from the real thing. My question is , is that kind of difference normal or the error of the Fenix is beyond tolerance. The only thing that is different is that I have de Fenix with 181 max beats per minute in settings, and in the lab they thoughts that my mas HR was 179 (I'm 48). The Fenix value for the day before the test was 57 and the test was 62.
Probably is better to consider not the value in itself but the evolution with your training .
Thanks ciq.forums.garmin.com/.../1255681.jpg

0 FlipStone over 7 years ago

Well, yeah... it's an estimation and no exact science.

VO2max is calculated based on heartrate, max hr (so yeah, if these differ between your garmin settings and the measured stuff this also changes things a bit) and intensity/pace as far as I know. But it can't adjust for things like temperature, you having a cold, being hung over, etc.

But most of the time the watch overestimates it btw, so that it underestimates is more surprising.

0 Former Member over 7 years ago

Using a footpod should (in theory) increase accuracy a bit, since GPS pace will probably be all over the place, so that may help if you're relying on GPS for pace. As FlipStone said though, usually this results in an overestimate for the times the GPS pace shows x2 higher than actual. Also, I assume you're using a chest strap HRM? Agree on using evolution of the value vs the value itself... it goes for all of these readings on a consumer device, since the only thing you can 100% rely on is the timer!

0 Agepi7o over 7 years ago

Thanks. Yes , I?m using the chest strap HRM. And I don't really care about de VO2 max figure, only its (my) evolution with training. The Lactate threshold value of the Fenix is also a bit under the real test (168 the test and 164 the Fenix). I was only wondering which one is more reliable.

0 Former Member over 7 years ago

Just to verify the 'reliability' of your VO2 Max test, why don't you go back to the lab and do it again? I'll put money on it your scores are different, because these number are always changing. Of all the things I'd grip about with Garmin this is probably the least offensive subject. For all the value they provide you when this stuff is working properly it does quite a bit of good.

0 Agepi7o over 7 years ago

I intend yo do it. But I?ll wait a while because I don?t know how ro convincente my wife I need to .

0 mcalista over 7 years ago

Garmin licences the VO2Max algorithm from Firstbeat. Their white paper on the topic (including a section on accuracy) can be found at https://assets.firstbeat.com/firstbeat/uploads/2017/06/white_paper_VO2max_30.6.2017.pdf

In short, the expected error is approx. +/- 3.5 ml/kg/min. The paper does note that an incorrect HRMax does increase the error.

0 Former Member over 7 years ago

This has been discussed here also:
https://forums.garmin.com/forum/on-the-trail/wrist-worn/fenix-5x/1231903-vo2-max-performance-condition-and-stryd
Reading the paper from firstbeat would suggest that using a footpod would give a more accurate estimate but from the comments here it gives a really low estimate. For me is 44 now without a footpod and under 40 with a garmin footpod. I started to use the footpod only indoors.

0 Agepi7o over 7 years ago

Garmin licences the VO2Max algorithm from Firstbeat. Their white paper on the topic (including a section on accuracy) can be found at https://assets.firstbeat.com/firstbeat/uploads/2017/06/white_paper_VO2max_30.6.2017.pdf

In short, the expected error is approx. +/- 3.5 ml/kg/min. The paper does note that an incorrect HRMax does increase the error.

Thanks, that error plus the change we expect in our normal life (better or worse days) would suffice to explain the differences. In my case I?m pretty sure that it also counts the fact that I don?t know exactly what is my real HR Max .
Nevertheless the important thing to pay a mention to is the evolution of those figures and what your body tells you about it.