VO2 Max Testing and Ventilatory Threshold: Endurance Testing for Runners

VO2 max and ventilatory threshold are two terms that many runners want to know to help them improve performance. Unfortunately, they’re not the best metrics for determining your training or potential. You’d be better off building your endurance with more volume (or a triathlon program to reduce injury risk) or by getting stronger.

I recently participated in an exercise study that included VO2 Max Testing and measured several key indicators for endurance, including my ventilatory threshold. The endurance testing I did wasn’t specifically geared for performance improvement (it was measuring progenitor cells in my blood before and after exercise), but I gathered a lot of valuable information.

My VO2 Max was measured on a treadmill using an incline test method. Every two minutes, the incline increased. It started at 0%, then went to 3%, 6%, and finally concluded 8% when the test concluded after 8:30 of running.

My VO2 Max result, 69.1 ml/kg/min, is pretty good and I’m pleased with it. But I’m surprised it’s so high because all of my race times predict a lower score. My mile PR of 4:33 predicts a VO2 Max of about 66 while my marathon PR of 2:44:38 predicts a VO2 Max of about 59.

Ultimately, VO2 Max is not a good predictor of race performance. Steve Magness, an accomplished runner, coach, and exercise physiologist, explains the “Fallacy of VO2 Max” in a great (but long) post. The conclusions that I draw from this article is that VO2 Max does not change in trained athletes and it doesn’t correlate with performance. So why try to improve it?

A more useful metric is lactate threshold – or the point at which lactate starts to increase dramatically in the blood. The LT can be improved upon in training through long runs, tempos, and an overall high volume program.

Unfortunately, I didn’t get my lactate threshold tested. But my ventilatory threshold was measured which is very similar. The VT is the point when respiration increases significantly due to the accumulation and exhalation of metabolic by-products.

VO2 Max and Ventilatory Threshold Testing

Below are several graphs that visually depict my results.

Summary Table: Vo2/Ventilatory Threshold and Blood Work

VO2 Max and Maximum Heart Rate

Pulmonary Ventilation and Respiratory Exchange Ratio

Researcher’s Analysis

“From top to bottom, these charts show your (i) oxygen uptake, (ii) heart rate, (iii) pulmonary ventilation (rate of air taken in & breathed out by the lungs), and (iv) respiratory exchange ratio during your max test. The x-axis (time in minutes) on the bottom panel corresponds with all four panels.

Your max VO2 was 69.1, which is considered very high and is typical of high-level endurance athletes. Healthy sedentary people your age may have values of ~45 ml/kg/min, whereas world class athletes (e.g. Olympic runners) may have higher values, e.g. high 70’s to more than 80 ml/kg/min, but only the tiniest minority of runners ever reach the level you’re at. You should be pleased with this result, as you are clearly a highly-trained athlete.

Your ventilatory threshold (VT) data are probably most useful for you. VT is closely associated with a metric you have probably heard of called the “lactate threshold”, and both are used as indicators of training status. Your VT is indicated by the vertical line crossing all panels. This occurred at 82% of your VO2 Max; the VT of some elite endurance athletes has been recorded at >90% of their VO2 Max.

Your heart rate of 169 beats/min at your VT could be used to guide your training. Essentially, you can train to increase endurance performance by regularly working at higher intensities (heart rates) than your threshold.

The data shown in the bottom two panels, pulmonary ventilation and respiratory exchange ratio are what I actually used to calculate your VT, so I include them here but they have little applicability to training and racing situations for you.”

Let’s Get Nerdy: Help Me Analyze!

This is admittedly a far more scientific, in-depth, and nerdy post than I normally do here at Strength Running. I would normally not post this, but I recently had a good discussion with a new runner who was trying to measure his VO2 Max so he could predict his future race results.

Like I mentioned, VO2 Max is not a good predictor of race performances. It doesn’t change in trained runners and can change little in moderately trained runners. So why train to improve it? Why even pay that much attention to it?

If any of you have a background in exercise physiology, have done any testing yourself, or just want to chime in, please do in the comments! Are there any actionable lessons I can take from this experience? What is the most valuable data here? How can I use this data to alter my training and improve as a runner?

If you’d rather have a private conversation, please email me at support@strengthrunning.com. I’d love to hear your thoughts. If we can learn a lot from this discussion, I’ll post a follow-up “lessons learned” article so we can all become better runners!

Please share this post with anybody that might be interested!

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  1. Given that only the aerobic aspects of metabolism influence the amount of oxygen we use during exercise, is your question actually about why we bother with aerobic base training?

    In that regard, I would say the short answer is that we need to maximize both our aerobic and anaerobic capacities to maximize our endurance and stamina, so we can run fastest over long distances.

    Well trained athletes reach a VO2 Max plateau which tells us they have seen as much improvements as they are likely to see in their body’s ability to fuel their activity using aerobic (oxygen-using) metabolic pathways. The fact that VO2 Max doesn’t correlate well with increased performance once this physiological limit has been reached is not an indication that these aerobic pathways have nothing to do with performance. It’s an indication that further improvements will come from increases in our capacity to fuel higher-intensity bouts of the activity with anaerobic mechanisms, or through other improvements in running efficiency.

    That’s more-or-less my take on it (as a physiologist).

    • Thanks for commenting, Mark. It’s my understanding that it’s very difficult to reach an individual’s maximum aerobic potential. This is why we see elite runners still doing 120+ miles per week after over a decade of high volume training. There’s still aerobic progress to be made.

      In my situation, I think I have a long way to go to approach my maximum aerobic development. I used to get a lot of injuries so there were periods of no running. So I’ll still continue working on that. Are any physiological shortcomings/inefficiencies revealed in this data that I can work on in training?

  2. Fitz, you’re right. It is very difficult, because athletes seem to reach a plateau… BUT, you also eventually reach a plateau above which you see little or no increase in lactate threshold. An optimal combination of aerobic and anaerobic capacity is (theoretically) what an elite athlete would be looking for, but because we are each born with different genetics, the optimal mix can be different for each athlete.

    An interesting thing about developing aerobic capacity is that it is the best way to improve your low-end “I could go forever” pace… While that doesn’t determine what your time will be in a race, where you’re pushing beyond that into anaerobic intensity, it does mean that you don’t even start going anaerobic until you’re running a bit faster than if you aerobic capacity (reach VO2 Max) is lower.

    Because people have physiological differences due to genetics and a range of other factors that make their rate of oxygen use vary among runners moving at the same pace, the VO2 Max number should be considered ‘personal’ in my view. Use it to judge changes in your own aerobic condition, not to compare mine with yours. That’s where it’s utility comes in.

    Still, when you train to improve your VO2 Max, what are you really doing? You’re simply training to improve your aerobic capacity, which relates to endurance, which relates to aerobic pace but not so well to race pace, where how much anaerobic stamina (or how high your lactate threshold) is makes the difference.

    It is noted, more in cycling than running I have seen this, that if you do ALL of your training at aerobic paces (Heart rate Zone 3), it can become very difficult to actually push up into Zone 4 to Lactate Threshold. Just as if you train with sprints, you can get quite fast (almost completely burst anaerobic effort), but be unable to complete a distance race!

    In terms of aerobic and anaerobic potentials, a way to think of it is that you have “actual” potential (the true biological limit), and “realized” potential (the best you can manage to reach under the most rigorous training regimen possible given all the other demands of life). An elite athlete may be somewhat free to train much more rigorously than the rest of us, so their “realized” potential is a lot closer to their “true” potential, than the average person. Still, it’s worth it if you are competing to win or set a world record to develop the heck out of both aerobic and anaerobic systems through long runs and threshold runs.

    You see some people advocating for JUST interval training, and they can argue quite forcefully and can point to a few cherry picked research studies which show that people who have not previously done a lot of interval (threshold) training, who then start doing it, improve their performance (usually studies on trained athletes), and VO2 Max AND performance (usually studies on couch potatoes). This result isn’t too surprising, as a couch potato’s realized VO2 Max is limited by deficits in muscular strength, neuromuscular development and coordination, and aerobic capacity to start with, and that aerobically conditioned athletes who have neglected threshold training will have a lot to gain in the way of performance by increasing their lactate threshold, but very little to gain by continuing aerobic training at the same levels they have been working for an already extended period.

    Most people early on, really need to work on building the best aerobic base they can… Which means, build gradually up to higher mileage (as much as they have time for) at an easy to moderate pace, and then gradually begin adding speed work in. One lesson is that if you don’t increase both your distance and the intensity of your speed work over time, you don’t get any faster in races.

  3. I should add, however, that you kind of throw all that away if you overtrain and don’t alternate hard with easy workouts and include some rest periods and easy weeks now and then, to give your body a chance to catch up.

    • Mark,

      Thanks so much for this analysis. We’re in total agreement here about the progression of training – starting at easy mileage as a new runner and progressing to higher volume/more intensity years down the road as their base is built.

      It’s also interesting to listen to the “all aerobic” vs. “all interval” debate. The best analogy I’ve heard (I forget from where) is that training is like a soup. You have to mix everything in the pot, but the order and amounts have to vary depending on how you want it to taste. The same is true with training. You need all the ingredients, added at the right time and in the right quantities.

      Thanks for stopping by and I hope you can share your perspective on future articles as well.
      – Fitz.

  4. Great discussion here! I’d love to have a similar test done on myself just to satisfy my scientific curiosity about this stuff. My take is that training can increase VO2max to a point, but once we reach that point, little more can be done to improve it. Most well trained athletes can’t do much to further improve VO2max. What can be achieved is an ability to train/race at a consistent level at a higher percentage of VO2max without going anaerobic. As was indicated in your results, if you could get your LT somewhere around 90% of VO2max instead of 82%, your performance would improve more toward predicted levels. I’m not as sure how high it’s possible for an individual to push LT as a percent of VO2max.

    The example I use in my class relating VO2max to performance is to compare Lance Armstrong to Alberto Salazar. Lance has a higher measured VO2max compared to Salazar in his prime, but could not come close to beating him in a marathon because performance in a given sport or distance is dependent on far more than just VO2max. One thing that pops into mind is muscle fiber composition – largely genetic, and probably not a whole lot we can do about it via training. Another is economy – how efficient are you at performing a given event without wasting excess energy.

    In the end, someone with a higher VO2max has a higher aerobic ceiling, but in a race, picking the winner by going with the person with highest VO2max would be very unwise.


    • Thanks for the analysis Pete. I think we’ve come to the same conclusion that the variable I (and all runners) should focus on is pushing my LT closer to my VO2 max. It’s what is most dependent on training and what I have the most control over.

      Funny you bring up Lance’s marathons. I remember before he made his debut there was so much talk in the running community about his potential to be sub-2:10 fast. That clearly didn’t happen despite his high VO2 and conditioning. He’s one of the best endurance athletes in the world, yet I can beat him in a marathon!

      Developing a strong aerobic engine by pushing my LT higher will continue to be one of my primary training goals. Volume, tempo workouts done at LT, and challenging long runs can accomplish this. I won’t be afraid of ripping some fast intervals on the track every now and again though. 🙂

  5. hi. this is confusing.

  6. If you would like to actually get tested, there is a company called New Leaf that sells VO2 testing machines to gyms and coaches- if you go to their website which I listed you can search for a location near you that would be able to test you. We just bought one for our Chicago Athletic Clubs and I am absolutely loving the data we are getting from it- it tells you precisely what your different training zones are based on your test results and then gives you a training protocol to follow that you can plug into certain HRM. Think about the 220- age formula and how huge the variability is between individuals of the same age. It is definitely worth getting done to improve your performance!

    • Thanks Matt…but, did you read the post? I was tested in a sports performance lab…

      • Hi Fitz,

        I understand that you were tested in a sports performance lab but I know that a lot of other runners are interested in this same type of testing and would love to have the same information available to them which is why I included the link (which I didnt realize pops up only when you click on my name).

        When I first started doing triathlons I would have loved to have known about a place where I could have taken the test myself. It was a great article, thanks for the explanation! I just wanted to let your readers know where they could look to get tested (not only at our clubs, but anywhere there is a New Leaf testing site). I truly believe in the value of this type of information and just want to get it out there!

  7. One test that I don’t see that was done is the Lactate Threshold test. One area you may be experiencing where others may have an advantage is how much lactate acid your body is producing. A high lactic acid level would lead muscle fatigue.

    • Hi Cameron – you’re right, an LT test wasn’t performed because it wasn’t in the scope of the research that was being done. Too bad for me! But the ventilatory threshold is similar. I think the bottom line of this test, and all of these tests, is that while VO2 Max can be improved slightly, your biggest gains can be had by improving your LT with volume, high-end aerobic work, and tempo workouts. That’s where you’ll get the most fitness bang for your training buck. Thanks for stopping by!

  8. Hi, Fitz, I am sorry, but determining the ventilatory threshold (VT) by VE and RER as it is done, is incorrect ant not reliable. The VT is calculated by the changes of two other parameters of the respiratory response to graded exercise – the respiratory equivalents of O2 and CO2. So, forget about these 82%, it is not correct. The anaerobic threshold is determined most accurate by step-by-step lactate measurements and not so accurate, but reliable, by VT as described above. Find more sophisticated lab!

  9. Rich Wilson says:

    Was that 186 max HR an actual pushed max, or just the max you happened to attain while doing other tests? Does anyone happen to know just how variable that 220-age number is? In my very limited experience it doesn’t seem to be worth much. I’ve gotten mine (on bike and running) 10-15bpm over what my 220-age ‘should’ be (the range has reduced with age, but I’m also not as fit at 45 as I was at 28).

    • Hey Rich – the max HR was just the max that I attained during this VO2 Max test. The 220-age number is VERY variable and isn’t a great predictor of your actual max – there are too many other things that can factor in to your max heart rate. Thanks for stopping by!


  1. […] VO2 Max Testing and Ventilatory Threshold: Endurance Testing for Runners […]

  2. […] I remember back when he was preparing to run his first marathon. Many runners and cyclists predicted his finish time to be among the elite – around 2:10. He does, after all, have a VO2 Max of about 85 (non-runners are in the 40′s – last year mine was measured at 69). […]

  3. […] would be likely with the introduction of EPO into a riders training regime.  Equally the ventilatory threshold or VT gives a further indicator of improvement levels enabled by the elite athletes intelligent […]