I saw this online and was wondering if people can confirm accuracy based on their numbers (especially if you have a lab measured VO2 Max):
VO2 Max= 12 x (5 min power in watts/kg) + 3.5
That formula matches my garmin estimate within 1 point, but is about 4.5 points higher than actual vo2max lab testing. So, pretty close but not perfect. A fix formula like that is never going to work for everyone since there is no way to know v02max based on watts since efficiency varies by individual. But it should be reasonably close for people with average efficiency.
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Off by about 5% for me. Haven’t seen this one before.
Would be a bit skeptical on first glance as 5min power can have a large anaerobic contribution, which can be highly variable between people. Which would seem to suggest that this would have poor precision.
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It’s not accurate. It’s not even really necessary. If you want to know your VO2max, go get it tested. Otherwise, what most of us care about is performance, and there are plenty of ways to get that using a power meter. No need to use a made up model equation for a number that is relatively meaningless anyway.
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That equation appears to be from a typical linear relationship between power and VO2. 3.5 is resting metabolic rate and 12 is the slope of VO2 to power. But, the 12 can range from 11 - 14 and the resting rate also has a range (perhaps +- 1 ml/min/kg).
The equation gives me between about 43 - 46 ml/min/kg, but I measure between 51 - 54 ml/min/kg with my metabolic cart.
Garmin gives me a VO2max of 52.
I have about 10 power to VO2 correlation equations (5minute power, 4minute power, slopes of various ramp rates, etc.) in Excel and they’re just not that useful.
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Approx 12 years ago I had mine lab tested at 51.7
I’m fitter, but a lot older now and Garmin Fenix puts me around 50 to 51 atm
This calculation puts me at 50.6
Probably is close enough, tbh
Intervals.icu uses this formula: VO2 max = 16.6 + (8.87 Ă— 5-min watts per kg)
For me that comes out quite a bit less than the OPs formula (61.8 vs 64.7). My Garmin says 61.
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Best 5 minute power recently for me was on the Ramp Test. Using this formula, it underestimates V02 max by 4 points, a V02 max that was measured on a metabolic cart. The last 5 minutes of a Ramp Test is certainly an underestimation of 5 minute max power, so this formula may be pretty close!
This is not surprising considering the exponential nature of strain on the body when intensity increases. How does the last 4 minute average line up?
According to this my VO2 max would be 59. This is at age 35 and without having a 5 min power that have been all out only for this purpose.
I have not ben to a lab to test it or do I wear a Garmin, but my first thought is that seems extremly high compared to how I see my own fitness level.
Ive not got a wearable only an Edge, Power Meter and HRM to estimative VO2 max. Going by that the formula is slightly low of Garmins farcestimate. Garmin seems to be heavily influenced by group or solo riding. On a group ride it almost always falls by a point after a group ride. At the moment it sits for me at 59parts as a 49year old fallen from 62 a month back when I was doing more solo work on the power meter equipped bike and riding outdoors with the winter bike which doesn’t have a power meter.
Any real simple formula like that will not be accurate.
But I’d step back and ask myself: what do you need that number for in the first place? Do you want to track your VO2max (≠MAP or some such) to improve that number?
Using last 4 minutes of ramp test, that formula would still underestimate my met cart measured V02 max by 7%. It feels like something like this could be dialed in to fairly accurate, by looking at a large cohort of TR athletes who did both met cart VO2 test and ramp tests. That would be a good study.
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I don’t need the number. Just “academic” interest.
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What would you expect that study to show? It’s already well established that the relationship between power output and o2 consumption varies significantly by individual. All a study would do is help determine/confirm the range, but still can’t provide a formula that works for everyone.
Same. Those that are mentioning garmin predicted VO2, is that just based off an edge, or do you need to wear a garmin watch regularly to get a more accurate estimate?
My 5 min power PR is not an accurate number as I’ve never done an all out 5 min effort. My 5 min PR was part of an all out 15 min effort, and only 4 watts less than the 15 min average. I’d like to have an actual VO2 test done this year.
Not even close
With an edge you need a PM and HRM but I think some of the more expensive watches calculate of Optical HRM. My watch maybe does too but I never record a run. Ive no idea what is more accurate but I’d favour the cycling (edge) VO2max estimate just because it uses more data inputs.
What Is VO2 Max Estimate and How Does It Work? | Garmin Support
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I don’t use Garmin at all, so I had no idea that the computer gives you an estimated VO2 Max 
I use Wahoo, PM and HR.
And yeah, I have no idea what to use my VO2 Max value for. Or, if I had access to free test of it every month it could be interesting, but I don’t..