A few weeks about, I wrote about the patients I’ve been seeing who come in for a preventive cardiac evaluation after reading Peter Attia’s book Outlive.
It was pretty surprising to me to see how many questions I got about VO2 max testing after the article - it’s clear that this is a topic that resonated with many people.
And since VO2 max is having a bit of a moment in the fitness world, I thought it was worth talking about how I think about the value of getting this test done to assess your overall health.
When someone is asking the question “should I get a VO2 max test?”, what they’re really asking is whether the cost and annoyance associated with this test is worth the information that you get from it.
After all, getting your VO2 max tested is probably going to cost about $200 and take at 30-60 minutes of your time, not including travel to and from the specialized lab that does the testing.
So I’m much more interested in the question of whether VO2 max is uniquely important or whether there are other cheaper and easier ways to figuring out what VO2 max is telling us.1
A high VO2 max is linked pretty closely to good health outcomes
The relationship between high levels of fitness and health is pretty clear: a higher VO2 max means you are less likely to have a heart attack or die.
To take it another step farther: elite cardiovascular fitness may be the best predictor of the likelihood of dying that we have.
There’s a paper from JAMA in 2018 that looked at exercise performance on a treadmill stress test and how that predicted someone’s likelihood of death.
What they found was pretty shocking: a low level of fitness compared to an elite level of fitness2 was a better predictor of your likelihood of dying than having end stage kidney disease, meaning that you’re on dialysis:3
Here’s another way that the authors describe the likelihood of dying based on level of fitness:
The relationship is pretty clear: the fitter you are, the more likely you are to be alive.
VO2 max is a great metric for assessing overall fitness level for a handful of reasons:
You can’t really “cheat” the test
It provides a marker of your overall cardiovascular fitness level that isn’t subject to effort (like running a mile would be)
It’s very well validated across many different populations
Are we sure that there something unique about testing our VO2 max?
VO2 max may have a long track record of use by elite athletes, but it isn’t the only way of assessing your fitness level.
I wrote last week about how one of the most important pieces of information you can get from a stress test is your exercise capacity:
This is a graphic about the risk of death from all causes as it related to cardiorespiratory fitness (CRF) as measured with a plain old treadmill stress test - you can see pretty clearly that the least fit people are the most likely to die:
That JAMA paper I cited above used treadmill stress tests to evaluate fitness level too.
So if the most influential paper in this space didn’t send patients to a lab for VO2 max testing, are you sure that you need to spend the time and money to do it?
The more I dig into the data here, the more convinced I am that you can get essentially all of the information from a VO2 max test in other, more simple ways.
There’s quite a bit of data in support of the idea that VO2 max correlates well with a number of other much more easily measured metrics of fitness.
Here’s data showing the tight relationship between 12 minute run distance and lab tested VO2 max.
Here’s more data showing that you can estimate VO2 max pretty closely by using 1 mile walk time and your heart rate (along with some other variables).
A 1.5 mile run time is also a great surrogate for VO2 max:
In other words, VO2 max provides an objective measure of your fitness level, but it isn’t particularly unique in the insights that it provides.
Is the journey or the destination?
I think an interesting question to ask about this is whether the result on the test matters more than the way you got there.
In other words - is VO2 max the thing that determines your longevity, or is the benefit accrued from the exercise you needed to get there?
It’s an interesting thought experiment.
Do the results matter more than the methods?
And does a high VO2 max (or treadmill stress test time, or fast mile run) mean that you need less exercise?
Or does is the benefit really accruing from time that you spent exercising and the high VO2 max is just along for the ride?
My gestalt is that it’s impossible to ever answer this question and that these things are too entangled for it to matter, but if your VO2 max stinks despite the fact that you’re exercising a lot, it probably means that your exercise isn’t all that effective.
Just because a VO2 max isn’t unique doesn’t mean you shouldn’t understand your fitness level
When we think about things that move the needle on our overall health, exercise is might be the biggest one.
The advantage of seeking out a longevity doctor4 movement is that they can quantify how you’re doing.
What gets measured gets managed - if you don’t know how well you’re doing, you can’t know what you should be trying to improve.
If it will motivate you to go get your VO2 max tested, then, by all means, you should go for it.
But testing yourself on a 1 mile run or a 1.5 mile run as a marker of fitness level is probably good enough.
You could even just go do a treadmill stress test and see what stage you get to on the Bruce protocol.
The first principle is that you must not fool yourself, and you are the easiest one to fool
We are all dishonest with ourselves about how we are doing.
Fitness is one of the areas where it’s easiest to bullshit ourselves.
The benefit of a metric like VO2 max is that it holds us accountable and we see how we really stack up.
If you’re trying to assess your overall health, my strong recommendation is that an objective measurement of your cardiovascular fitness is an important part of that assessment.
And so for most people, I don’t think there’s anything special about a VO2 max test.
But like many things in health, if you don’t know your numbers, you are really flying blind.
If you wouldn’t go years without measuring your blood pressure or your cholesterol, then why would you go years without measuring your exercise capabilities?
And if you’re like the vast majority of patients that I have and people that I know, you’re probably more interested in whether the cheaper and easier method is a good enough assessment than you are about trying to optimize in order to do something 5% better than 200% more annoying.
Levels were defined by percentile achievement in peak exercise capacity on the stress test.
Kidney disease was the medical condition linked to the worst mortality rates.
Or just a good preventive cardiologist.