Depends on how much of an increase you are seeing. For sure garmin won’t be completely accurate either way but can probably give a decent benchmark. Fwiw i saw a 7% increase in 4w during a training block where the results were lab tested, and if you are starting unfit you can definitely see more.

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Terrible Tuesday’s Triathlon

For some reason the graph is not uploaded - but from about 47 to 53 in 4 weaks hence about 12%

Last summer, when I started training again (after several years off) I saw my VO2 jump from 41.4 ml/kg/min to 47.2 in two months. Those weren't maximal tests with the respirator and all that, but they were in a physio lab on university campus on a treadmill...so relatively accurate. Since then the gains have been much more gradual and I'm now at about 53 or 54...which took about 8 months to to achieve (though I wasn't necessarily "training my ass off" for all of that).

Anyways, not sure if that helps any...

12% in 4 weeks doesn't sound obscenely rapid.

I'd expect something similar in a build or race phase if I haven't done much high-end work. I mean, 10% would only be 30-40 watts, generally. My five minute power will usually increase by that much from winter to race time.

Make sure you double check what it’s using as the upper HR. If you have it set to auto detect your max HR, and you get a spurious HR>200, it will calculate your VO2 max based on the higher max HR value and falsely elevate your reading. It’s better to just set your max HR and turn off auto detect

The Garmin thing is complete utter BS. It's for entertainment value only. Just as an FYI in the last 2 months mine has varied from 58 to 70.

x2.

I've seen my 5k prediction go from 16:54 to 18:07 in 2 weeks.

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@floathammerholdon | @partners_in_tri

Vo2max can increase a lot, very quickly. For the lucky ones with sky-high VO2s, that means rapid improvement to high levels in short distance racing!

The bummer part is that those rapid gains plateau fairly quickly (2-3 months of hard training).

This is why there are quite a few new runners/triathletes who get enamored of their remarkably rapid progress in their first 3-5 months of training, as if they continued their improvement trajectory for a mere 16-20 months, they'd be pro/elite level! Alas, then invariably the plateau kicks in a lot sooner than they think and you never hear from them again...

While I can't say it's good for everyone, Garmin's VO2max prediction is very close to what I tested in a lab.

Agreed. Also for the OP to consider is weight loss. If that has changed and you have a scale connected to Garmin (or if you manually enter weight) VO2 will go up as well.

To those saying it is garbage, I disagree. Is it as accurate as a lab test? Nope. Generally for me it isn't too far off from the lab and it does seem to trend with fitness increases for me.

It is garbage. Look, I am a 40 year old guy who has primarily been a runner my whole life. 2 weeks ago my running vO2max was 69 on my 935. It was predicting a marathon PR in the 2:20s. I've never run faster than 2:39, and that was 7 years ago.

Today it has my vO2max at 63, and the marathon prediction is 2:36. What changed in 2 weeks? Well, I ran in heat and humidity which slowed me down for the same heart rate. It actually dipped to 59 last week as I ran in that heat. Came back home to the bay area and now it's back at 63, which is still wrong...by a lot. I see it do the same thing when I do hilly runs, it takes my vO2max and decreases it by a ton because all it's doing is looking at pace/HR/

So there's two issues here. 1) vO2max does not bounce around this much and 2) It doesn't know how to factor in anything.

In short, it's crap.

I wonder if there is a difference in how this works between differing Garmin units (I have a different unit than you do). My Garmin VO2 predictions are within +-5 ml/kg/min of my lab tests and they do trend with overall fitness. So not perfect but not bad. I don't dispute what you are saying I'm just generally curious why it trends well for me and not you. I've never looked at the pace calculator so I can't comment on that.

So you’re not differentiating watts from VO2.

Huh.

How are watts described in ml/kg/min?

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no sponsors | no races | nothing to see here

I'm giving an example of watts at vo2 max via a 5 min cp (which tends to line up well for me).

You can track it in wko4.

Today mine went up to 65. Weeeeee, garbage in garbage out!