02/26/2026
The Overreaction to VO₂ Max Is Coming. Here’s What Coaches Need to Know.
You can feel it, can’t you?
The swing of the pendulum.
First it was:
10,000 steps.
Then HRV.
Then cold plunges.
Then everyone discovered VO₂ max and suddenly your aerobic capacity became your moral worth.
And now the backlash is here.
Eric Topol — in a widely circulated post on his Ground Truths Substack wrote an article entited "The Flawed VO2 max Craze"— steps into the arena and says:
“Hold on. Most of the mortality everyone is attributing to VO₂ max isn’t even directly measured VO₂ max. It’s MET-derived cardiorespiratory fitness data.”
And here’s the uncomfortable truth:
He’s not wrong.
He’s just not finishing the sentence.
Let’s Start With the Data (Because Coaches Should)
If you strip away the influencer noise and look at the literature, the mortality signal around aerobic capacity is enormous.
A 2024 overview covering 20.9 million observations across 199 cohort studies found a consistent inverse association between cardiorespiratory fitness and mortality (Lang et al., 2024).
Each 1-MET increase is associated with 11–17% lower all-cause mortality (Lang et al., 2024).
Side note: A MET—Metabolic Equivalent of Task—is just a fancy way of saying how much oxygen you’re burning compared to sitting on the couch doing nothing. 1 MET ≈ 3.5 mL/kg/min, aka your metabolic idle RPM.
High versus low fitness cuts mortality risk roughly in half (HR ≈ 0.47) (Lang et al., 2024).
That’s not biohacker fluff.
That’s population-scale signal.
In some datasets, the least fit individuals have 4–5 times the mortality risk of the elite.
That’s in the same conversation as smoking.
Topol is right about that.
He’s also right that:
• Wearable VO₂ max is noisy.
• Wrist optical heart rate is not gas exchange met cart data.
• AI systems are now “grading” people’s longevity based on shaky estimates.
• Single-metric obsession is dumb.
Yes.
Shocker -your watch isn’t measuring oxygen consumption breath-by-breath, so it is not doing a lab grade measure of your VO₂ max.
It is doing and educated guess via an algorithm compounded typically by optical based heart rate assessments.
What this means in English - if you are rearranging your training week because your Garmin dipped 2 mL/kg/min after a bad night of sleep, that’s not optimization..
.thats superstition with Bluetooth.
If you want a signal worth tracking, do max 2K on the Concept 2 rower or if you can run without your gait pattern looking like an inflated tick with a pole up its ass, then do a 12 min Cooper Run Test. These are max tests that you can translate to a VO2 max score. They are not perfect, but you can track your output changes in them over time.
But Here’s Where the Wheels Come Off
The leap goes like this:
“Most mortality data uses MET-derived cardiovascular respiratory fitness (CRF), not direct VO₂ max.”
Therefore:
“We should focus on METs, not VO₂ max.”
That sounds clean.
It’s also incomplete.
Because MET performance and VO₂ max are not rivals.
They are different camera angles on the same engine.
METs are the scoreboard.
VO₂ max is the engine.
When someone performs at 12 METs on a treadmill, what do you think that represents?
Stroke volume.
Cardiac output.
Oxygen extraction.
Mitochondrial density.
Autonomic coordination.
In other words: aerobic capacity.
Which is what VO₂ max quantifies.
So when Lang et al. (2024) show massive mortality gradients across MET categories, what you are actually seeing is a gradient in the engine.
Measurement hierarchy is not mechanism.
You don’t dismiss horsepower because the dyno wasn’t the exact brand you prefer.
In short, the higher your VO2 max, the better your CRF is going to be.
The Mortality Signal Isn’t Fragile
Let’s go further.
In a 46-year follow-up of 5,107 men, each 1 mL·kg⁻¹·min⁻¹ higher VO₂ max was associated with roughly 45 additional days of life, and the top 5% lived about five years longer than the bottom 5% (Clausen et al., 2018).
Five years.
That’s not a rounding error.
Directly measured VO₂ max in the lab show similar patterns. Individuals in the highest quartile of measured aerobic capacity demonstrate dramatically lower mortality risk compared to the lowest quartile (Harber et al., 2017; Schumacher et al., 2022).
And here’s the part almost no one is emphasizing:
Change over time matters.
Each 1 mL·kg⁻¹·min⁻¹ increase in VO₂ max across ~9 years was associated with a 9–11% lower risk of all-cause mortality (Imboden et al., 2019; Laukkanen et al., 2016).
Static VO₂ max predicts.
Rising VO₂ max protects.
That is not a dashboard vanity metric.
That is adaptive capacity.
The Mendelian Randomization Mic Drop?
Yes, a 2024 Mendelian randomization study suggests genetically higher VO₂ max is not causally associated with longevity, whereas body fat and diabetes risk show causal signals (Kjaergaard et al., 2024).
Important.
…But read that carefully.
Genetically higher VO₂ max.
Not trained VO₂ max.
Genetics sets the ceiling.
Training determines whether you build toward it.
MR studies ask:
“If you’re born with higher VO₂ max potential, do you live longer?”
They do not ask:
“If you improve your aerobic capacity across decades, does risk fall?”
Those are not the same question.
And coaches should understand the difference instinctively.
Adaptation is not inheritance.
And crucially: the interventional literature asks a different question entirely. When people train and raise their aerobic capacity, mortality risk falls. That is the question coaches are operating on. MR studies don’t touch it.
The Gadget Circus Comes To Town
While academics debate measurement hierarchy, the real chaos is happening elsewhere.
Smartwatches are estimating VO₂ max from submaximal walks and extrapolations from coach potatoes to elite athletes.
AI systems are integrating those estimates into “longevity scores.”
People are screenshotting their cardiovascular future like it’s a stock portfolio.
Here’s the reality:
Validated metabolic carts, when properly calibrated, show ~2–6% error (Crouter et al., 2006; Martin-Rincon & Calbet, 2020) when doing a properly executed VO2 max test.
Wrist optical sensors estimating VO₂ max? That’s a different universe entirely.
And even lab VO₂ max testing must be performed correctly to be valid.
Tools reveal something.
They do not create truth.
Unless we’re talking about the band Tool. That worship is allowed.
The take away is to use a performance based test as discussed above as your marker for VO2 max rather than some rando sub max test run by an algorithm that you can’t see in the background…unless you are a true geek like your truly nerdy here and have your own metabolic cart.
Coaches, Stop Arguing About the Wrong Thing
The question isn’t:
“Is VO₂ max the single best predictor of longevity?”
The question is:
“Is the engine improving?”
If your athlete:
• Holds a given pace or power at a lower heart rate than six months ago,
• Returns to resting heart rate faster after a hard interval,
• Sustains output in the final third of a long effort where they used to fall apart,
• And shows upward aerobic trends over years—
You are increasing systemic capacity.
Whether you express it as MET improvement or VO₂ max improvement is secondary.
The organism adapted.
That’s the story.
That’s what needs to be monitored over time for improvement.
The Overreaction Is Predictable
Here’s the pattern:
Influencers oversell VO₂ max.
Wearables amplify noise.
AI grades people.
Academics push back.
And suddenly coaches start dismissing aerobic capacity like it’s the sugar diet.
That would be a mistake.
Because while the hype got stupid, the physiology never stopped being real.
Final Word
VO₂ max is not a magic longevity dial.
It is not a moral score.
And your watch is not a metabolic cart.
…however, aerobic capacity remains one of the most powerful integrated markers of systemic health we have to date.
Is it perfect?
Of course not!
As a coach, you want to focus on your clients / athletes that can:
Deliver oxygen under stress.
Clear metabolites efficiently.
Repeat output tomorrow.
And improve that capacity over time.
Train the engine.
Measure real output.
Track trends over time.
Apply violent consistency.
Rinse and repeat.
…And for the love of physiology, stop letting algorithms tell you whether you’re alive.
Much love,
Dr Mike
References
Clausen, J., Marott, J., Holtermann, A., Gyntelberg, F., & Jensen, M. (2018). Midlife cardiorespiratory fitness and the long-term risk of mortality: 46 years of follow-up. Journal of the American College of Cardiology, 72(9), 987–995.
Crouter, S. E., Antczak, A., Hudak, J. R., DellaValle, D. M., & Haas, J. D. (2006). Accuracy and reliability of the ParvoMedics TrueOne 2400 and MedGraphics VO2000 metabolic systems. European Journal of Applied Physiology, 98(2), 139–151.
Harber, M. P., Kaminsky, L. A., Arena, R., Blair, S. N., Franklin, B. A., Myers, J., & Ross, R. (2017). Impact of cardiorespiratory fitness on all-cause and disease-specific mortality: Advances since 2009. Progress in Cardiovascular Diseases, 60(1), 11–20.
Imboden, M. T., Harber, M. P., Whaley, M. H., Finch, W. H., Bishop, D. L., Fleenor, B. S., & Kaminsky, L. A. (2019). The association between the change in directly measured cardiorespiratory fitness across time and mortality risk. Progress in Cardiovascular Diseases, 62(2), 157–162.
Kjaergaard, A., Ellervik, C., Jessen, N., & Lessard, S. (2024). Cardiorespiratory fitness, body composition, diabetes, and longevity: A two-sample Mendelian randomization study. The Journal of Clinical Endocrinology & Metabolism.
Lang, J. J., Prince, S. A., Merucci, K., et al. (2024). Cardiorespiratory fitness is a strong and consistent predictor of morbidity and mortality among adults: An overview of meta-analyses representing over 20.9 million observations from 199 unique cohort studies. British Journal of Sports Medicine, 58, 556–566.
Laukkanen, J. A., Zaccardi, F., Khan, H., Kurl, S., Jae, S. Y., & Rauramaa, R. (2016). Long-term change in cardiorespiratory fitness and all-cause mortality. Mayo Clinic Proceedings, 91(9), 1183–1188.
Martin-Rincon, M., & Calbet, J. A. L. (2020). Progress update and challenges on VO₂max testing and interpretation. Frontiers in Physiology, 11, 1070.
