Use the number that's closest to your most recent real-world 5k race VO2 estimate using an online calculator. My garmin run Vo2max has me pegged a full 2 minutes faster than I can actually run a 5k.

I wouldn't trust a treadmill test. That 1% gradient is just an average estimate for training.

2 miles run test outdoors or 5k race.

I've always felt the Garmin gives a low estimate of VO2. I've done a laboratory VO2 test (on a bike) and I've never gotten closer my watch's run or bike VO2 to be closer than 8 of that lab number

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Matt

That is generally true but my Woodway is super accurate. And I like that I can fully run it right - control it. Also the Cooper test is 12 minutes and not a 5k.

Preferred would be 12 minutes on the track but finding a time with no 3 musketeers walking side by side is tricky

If you dig through the Firstbeat (now Garmin) white papers, they note that the accuracy of the VO2Max prediction is heavily dependent on the accuracy of your personalized HRMax. If you are using the age-based default, or the "highest you have seen in a 5K race", then likely the usefullness of the VO2Max estimate will be similarly vague.

It's not perfect, but I find it a reasonably useful tool. Definitetly gets most of us amateur hacks in the right ballpark and it's a good reference for seeing where we're at. I think it's important to realize that race predictor refers to your potential time based on your current estimated Vo2, not what you can actually do that day.

My Garmin was pretty accurate for where I'd expect my 5km time to be right now, then something happened after a brick and it's estimating my 5km and 10km to be slower than the pace I train at, never mind race at. It's completely out of sync with my relative VO2max readings too.

I would not have much faith in either number for accuracy. If you really care about your vo2max you need a lab test.
But what do you need vo2max number for? For me (beyond ego), the only benefit of the Garmin vo2max is progress over time assuming its consistent. Just like FTP

Here's a video youtube put on my queue the other day: Lab vs Garmin VO2 MAX - YouTube

I've no 1:1 for this as I've not done one, but reading enough on ST and the "wattage" forum I feel this is the way.

Primarily you run into folks whose VO2max either outpaces their LT for the test duration OR whose LT for the test is a very high % of their VO2max.

In either case, it's kind of a weird proxy.

I guess due to bike fitness that when running in the off season it thinks my run vo2max is something silly good. Sure, it may be. But.......it would NOT be if doing a maximal test due to LT constraints. If taking the time to train the LT up to a higher % of vo2max, then sure.

Just an example as to why I feel a lot of the run/bike tests with calculators can tend to be ego inflators or ego slayers. More of a parlour trick.

Take your test results, adjust to a 3km distance and plug into Daniel’s Vdot calculator.
You have a good vdot but suspect than 65vo2max is a high estimate
Just another watch since with two watches telling different times, you don’t know which is right

What is your use with the vo2max value? To track training improvement, compare to peers, just curious?

In school I did multiple vo2max tests in exercise physiology class. My garmin gives me a vo2max of 57-59 for both bike and run. In the lab it was tested at 72 on the run and 64 on the bike. Personally I would not use the garmin metrics to guide training. They seem to be based much more on performance rather than true physiology. I guarantee there are a ton of athletes that will outrun me in a race with a far lower true vo2max.

I watched the video and it is well done but my situation Is quite different. I can ride quite fast and never come close to the HR numbers I am getting when running fast. Thus my cycling numbers are less interesting to me. I did a group ride where we rode at 20 mph and my HR barely crested 100

But I will go to a a lab and have lactate and VO 2 max levels tested

14:30 5K equivalent for 72 VO2max on the run per online calculator!

 
14:30 5K equivalent for 72 VO2max on the run per online calculator![/quote]
That's way high.
14:30 is mid-low 60s territory.

-bobo

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"What's good for me ain't necessarily good for the weak-minded."

That's way high.
14:30 is mid-low 60s territory.

-bobo[/quote]

I just used this thing
https://www.omnicalculator.com/sports/vo2-max-runners


but this thing says about 70
https://runnersweb.com/running/rw_news_frameset.html?https://runnersweb.com/running/vo2.shtml

Garmin's assessment is algorithm based, and focuses on population averages. The Cooper test is again, an indirect test, based on population norms. Neither of these are accurate, but serve as useful data points to track progression over time. If your interest is in accurate VO2max numbers, the only way you will get those is to do lab testing with Oxygen collection (again there are several accepted protocols here, so if you want to monitor progression, you will want to ensure that the same protocols are used each time). Everything else, watch based, or indirect tests, will give you an estimate that is wrong (but statistically less likely to be wrong than unvalidated approaches).

It's like the old adage of 220-your age for max heart rate, it's accurate in less than 15% of the population, but that's less inaccurate than other indirect methods...

For most of our purposes, as long as we have some reference points to track progress over time, and use them consistently, that's more important than objectively accurate data.

Just shows calculators can be off...
In '89 I lab tested @ 72, best 5k was only 16:09. Not too efficient I guess.

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I saw this on a white board in a window box at my daughters middle school...
List of what life owes you:
1. __________
2. __________
3. __________

Exactly why I suggest not using vo2max to guide any decisions. A high vo2max number is good for identifying your potential and talent but it doesn't prove how fast you will race. At the time I recorded the 72 vo2max running my 5k was probably 17:45 and mile 4:55. Far from elite, but it shows that I have potential in this sport and my results are trending in that direction.

Sample size of one but ... my son (16 years old) is an avid runner and triathlete. He has been using a Garmin watch for a while so it has good data on him. For unrelated reasons he got a VO2Max test at a hospital lab. The Garmin and the lab matched exactly.