Timing of VO2 Max Test

Hi all,

My wife got me a formal VO2 Max test for my birthday. Just wondering how much the timing of the test matters. Should I schedule it at the end of a recovery week? Day after a high-intensity workout? Am I just thinking about it too much?

I get the overall principles and value of scheduled testing at regular intervals but this is likely a one-time thing for now and just want to make the most of it.

If it matters, I’m about to start a build phase leading into cyclocross specialty.

Thanks all!

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IMHO you should probably taper at least a little for it, could you ask the people that will be administering the test what they recommend?


Treat it like any other scheduled interval day. You don’t want to be carrying any excess fatigue, but you also don’t want a cold engine after extended rest. +1 on reaching out to the test site to better understand the protocol, suggested prep, etc. I’ve done a couple of them at the local university and they were very helpful and obviously work a bit with cyclists. You’ll want to make sure you can use your pedals and get a proper warm up if possible, make sure they have good cooling, etc… For me, I struggle on any all-out test like this unless I can get a decent warm up in (ie - not a 10 minute z2 spin). If you are into the science side of things, the test results can be very interesting. May or may not be useful in how you train, but still interesting stuff to know about.


Thanks @jiffylush and @grwoolf for your thoughts. Definitely plan on reaching out to the place for more general info.

I’m a data geek so I’m definitely excited about the numbers! I’m a die-hard TR plan builder/AIFTP person so not sure how much it’ll change my approach but excited nonetheless.

It’ll satisfy a curiosity but doesn’t give you much actionable data.

I’d do whatever it takes to score as high as possible. They’ve mentioned on the TR Podcast that a lower than expected result can be demoralizing.


Ha! Yeah, not too worried about the number itself. I’m hard to demoralize and I recognize that it has no impact on my actual performance. Just something I’ve wanted to do and appreciate the thoughtful gift from my wife.

I’ve had many done while participating in a study at my university at the time. Being tapered as if it’s a race won’t matter much, but I wouldn’t do a super hard workout or big long ride the day before. Just be sensible.

They’re measuring vo2max breathing (in mL of oxygen per minute). Your power at vo2max breathing will change over time. If you’re super fit, you can hit vo2max breathing and keep increasing power steps beyond it. For example, imagine a ramp test where you hit vo2max breathing at 420w and keep riding at that breathing rate until you fail on the 500w step. Despite the fact that you got all the way to 500w, your test result for vo2max breathing rate was already achieved at 420w (ie it plateaued).

I saw my number change about 15% from almost no training at all (illness and injury for a month or so) to a few months in a row of consistent training. It only moved about 5% increase from training with little structure but regularly to doing structured intervals consistently.

All that said, you can’t do it wrong or fail the test. It’s just a nice number to brag about! Lol have fun

Hi there - saw this thread and had a question. Has everyone fasted before the VO2max test? I’m set to do one using the PNOE - https://pnoe.com/ technology later this week and my administrator did not indicate it was necessary. But from some online searches it seems being fasted is important. Curious if others had to fast and if anybody has done one with pnoe test equipment and whether they were fasted.

Never heard of fasting before a v02max test, seems like a bad idea for a traditional test. Not sure about the PNOE thing, looks like it’s doing some things different from from a normal test.

I believe it’s a good idea to have a few hours between your last meal and the test just so you don’t have food digesting while you try to go all out.

Good luck with the test. I have a Pnoe and it’s a finicky device. Even using calibration gas, I get results that make me scratch my head. Do you know know long the administrator has been testing?

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I confirmed with Pnoe that one should fast from food and caffeine for at least 3 hours before test. Said it could slightly affect results with HR data, etc.

The technician has being doing the Pnoe tests for a couple years and metabolic tests for 20 so hopefully he knows what he’s doing. I guess if I’m disappointed with the VO2 number I’ll assume it was an error and if I’m satisfied, I’ll assume it’s correct :).

I do wonder what the range of results could be for the same individual doing lab tests over a short period of time. Hopefully not more than a few percentage points.

Best of luck.

Just so you know, the Pnoe can give reading several percent different and still be within spec. I’ve had this conversation with Pnoes inventor on several occasions.

The O2 sensor is rated at +/- 1% error on measurement. If you calculate VO2 from VE (also has +/-) and try to bound your measurement (+/-) you’ll see a several percent difference in possible VO2.

Also, the flow sensor also has a pretty large +/- on readings.

I have more than 200 hours of data on myself and I’m still looking to buy a better metabolic cart. Humans don’t make a portable and accurate cart yet, not even Cosmed. VO2Master is cool, but prone to error like Pnoe since it’s a consumer cart.

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There are studies that have been conducted for this exact purpose. There is variation day to day in humans. You might not get the same result doing the exact same protocol twice. All things to keep in mind when you interpret the results.

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Thanks, super helpful. Do you believe Pnoe offers sufficiently useful results or is a lab test preferable? I don’t intend to do these very often so would like to be confident in results.

Well, to be honest, I’d rather do CP testing or routine time trials to track fitness. Lab tests are insightful if you can do them often enough, but they’re prohibitively expensive. You also don’t typically get to pick your protocol, so that’s another downside.

I use the Pnoe for everything. Resting rates, sitting at my desk, running, hiking, cycling, chores, etc. I’ve used it for a ton of different protocols. I use it when doing regular workouts. I treat it as an expensive heart rate monitor. It provides ok data, but I follow all of Pnoes warm up and calibration protocols to a T

My advice is to do the test and see if you like what you get for the money. Be wary of the data, but don’t let my biases get in the way. I’d only recommend being tested with lab-grade equipment if you really want metabolic data. Or perform routine field testing with a power meter to avoid collecting confusing lab data.

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VO2 test is measuring how much oxygen your muscles can process, nothing to do with breathing rate or volume

Huh? Ever work with metabolic cart data or analyzing test data?

You have to measure ventilation to get O2 and CO2 consumption. You also get breath frequency with most metabolic carts when you measure ventilation. VE (vent. equivalents) are useful for identifying thresholds. Breath frequency can also indicate phase changes (thresholds).

They literally measure how much mL of Oxygen you breathe per minute per kg of body weight. Not sure what you mean by your comment

Call it ‘oxygen consumption rate’ if that makes you feel better. Perhaps that would be the more precise way of phrasing it, but in layman’s terms, they are measuring your breathing as you exercise at various outputs and measure how much oxygen mL you consume per minute per kg of body weight.

Got it. Frankly, I’m doing it just for curiosity and because I’ve had 4 kids over the last 6 years and finally had a decent training patch. And with all my interest in what traits I’m passing along to my kids, both good and bad, I’m hoping they get decent aerobic genes.

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Vo2 is calculated by measuring the oxygen in the air you breath out, and subtracting that from the oxygen in clean air. The reduction of oxygen in the air you breath out is assumed to be the amount of oxygen used by the muscles. Breathing rate and volume are recorded but have no direct effect on the VO2 number.

Eg an unfit person could be panting like a fish but using little oxygen, whereas an elite could be using twice as much oxygen and hardly breathing.