Garmin VO2 Max Vs Anaerobic Training Status

Hi all,

A quick question for the collective.

I’m currently doing SuPB MV so there are a few VO2 Max workouts in there. I record these on my Garmin 945 for upload.

I’ve noticed that my last few VO2 Max sessions have shown as being Anaerobic on Garmin when in fact I haven’t gone anywhere near my Anaerobic zone for either Power or HR. I’ve double checked all my zones are correct and they are.

I take the Garmin readings with a pinch of salt, but when things are incorrect it really bugs me.

Anyone else having this issue? Any fix? Pointless contacting Garmin, they are hopeless.


Which workouts?

Dashuik and Wild Snow. Not even close to Anaerobic as far as I can tell.

FTP on Garmin? Also the zones are a bit different, you can check that on and go to “device settings” → “user settings”

I had exactly the same this week, with those 2 workouts so doubt it’s anything with your setup and likely a Garmin issue

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Dashuik is 4x5-min vo2max, that one should get picked up as vo2max. Wild Snow is a bit of an in-betweener with 2-min intervals that are part anaerobic and part entry-level vo2.

The Firstbeat white paper offers up these settings as possible issues:

So check your Garmin settings for these:

My activity class is set to 7 because I workout 5 times per week, but weekly volume is averaging 7.75 hours for last nine months and so I’m going change it to 8.

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Thanks, all the settings are correct on GC

OK, this is what I expected. I thought most likely a Garmin issue picking up the intensity incorrectly. Garmin support are usually clueless but I’ll report it just so it’s on their bug list.

That’s interesting about Activity Class. Mine is also set to 7 but I’ll swap it to 8 and see what impact that has. All other settings are accurate.

Most workouts map cleanly into Training Impact / Primary Benefit categories:

but not 100% of the time.

Ok, thanks, but surely Garmin looks at Pwr/Hr zones to decide what is Ae or Ana?

That probably explains why garmin hardly ever gives me credit for high aerobic.

No, not really.

Garmin is using Firstbeat technology, a Finnish company they acquired last year.

Training effect is based on excess post oxygen consumption (EPOC). Basic information here:

More information here:

Interesting, thanks. I did Tunemah today and Garmin flagged that as VO2 Max when it is in fact a Threshold session (over-unders).

Thanks for this. I didn’t realize the Garmin activity class had any real meaning or effect. Mine has been set to 5 for years and it should be more in the 9-10 range. I’ll see if there’s any impact.

FWIW the last Garmin “VO2max” session was a workout a few weeks ago. That workout had 24 minutes of threshold, performed outside, so vaguely looks like unstructured over/unders. And WKO estimated I spent 21 minutes above 90% VO2max and 90 seconds above 95% VO2max. And my post-workout notes state I was doing a lot of “huffing and puffing.” Given the WKO analysis and my notes, I agree with Garmin’s classification as VO2max.

In other words, VO2max is not a power or heart rate zone. And without wearing a portable mask to measure oxygen consumption, you need more sophisticated analysis tools to determine if it was a VO2max effort. And a couple weeks ago those tools agreed with my own self-analysis of breathing associated with being in a state of near maximal oxygen consumption.

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I didn’t know activity class impacted Training Status. I have found that the only way I can get a reasonable reading on my Garmin scale is at Class 0, in reality I am a 10 (over 20 hours a week for years now). Maybe I will bounce it back to 10 and see if I get a difference, other than my BF% dropping to 6% :roll_eyes:

Every other metric has lined up well for me.

Actually, I am not seeing any reference that Activity Class effects Training Load. Can you post a reference?

Having just visited the Firstbeat site

Fitness Level - Firstbeat.

It seems their algorithm relies on comparing heart rate to speed. Does that create problems for trainer work? In ERG, you can sit at the same heart rate and significantly change recorded speed just by changing gear

That information is for VO2max estimation.

For training effect and related metrics, watch the 60-sec video on this page:

And read the white paper on the page… which has this basic algorithm for real-time EPOC:

and power data can be used to increase accuracy of estimates. But still, its an estimate and you can see that in the white paper where they compare measured vs estimated EPOC. The EPOC estimates are not perfect, and I’ve found they work well for me.

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