If I could point to one number that tells me more about a patient’s long-term health trajectory than almost anything else, it would be their VO2 max. Not their cholesterol panel. Not their blood pressure. Not even their family history. Their VO2 max.
That statement tends to surprise people especially high-functioning adults who arrive at our practice believing they’re in good health because their last annual physical came back unremarkable. But cardiovascular fitness, measured by VO2 max, is one of the most powerful predictors of all-cause mortality we have in medicine today. And in most standard medical practices, it is never tested.
At Aeternitas, VO2 max testing is a cornerstone of every member’s evaluation day. In this post, I want to explain why what VO2 max actually is, what the science says about its relationship to longevity, what a good score looks like for your age and sex, and what you can do to improve it.
What Is VO2 Max, Exactly?
VO2 max formally, maximal oxygen uptake the maximum amount of oxygen your body can utilize during intense, aerobic exercise. It’s the maximum amount of oxygen that can be taken in, transported and utilised by the body per minute. It is expressed in milliliters of oxygen per kilogram of body weight per minute (mL/kg/min).
When you exercise, your muscles demand oxygen to produce energy. Your lungs take in oxygen through breathing; Your heart pumps oxygenated blood to working muscles; your muscles extract that oxygen and use it to generate ATP, the cellular fuel that powers movement. VO2 max is the ceiling of that system the maximum throughput of the oxygen delivery chain from lungs to heart to muscle.
It is a measure of your cardiovascular engine at full capacity. And that engine, it turns out, has enormous implications not just for athletic performance, but for how long you live and how well you function in the decades ahead.
VO2 max is primarily determined by three factors:
- Cardiac output — how much blood your heart can pump per minute at maximal effort
- Oxygen extraction — how efficiently your muscles can extract and use the oxygen delivered to them
- Lung capacity — how effectively your lungs can oxygenate the blood
All three are trainable. That is perhaps the most important sentence in this article.
The Link Between VO2 Max and Longevity
The research on VO2 max and mortality is striking in its consistency. Study after study, across decades and populations, shows the same finding: the lower your cardiorespiratory fitness, the higher your risk of dying from cardiovascular disease, cancer, and all causes combined.
A landmark 2018 study published in JAMA Network Open followed over 120,000 patients and found that low cardiorespiratory fitness was associated with a higher risk of long-term mortality than hypertension, smoking, diabetes, and high cholesterol. Let that land for a moment. In terms of mortality risk, this particular study noted that being unfit was worse than being a smoker. Now that is maybe a bit of an exaggeration in general, and I certainly do not recommend that you take of up smoking if you consider yourself fit, but the data is clear – cardiopulmonary fitness is powerful.
| “Low cardiorespiratory fitness was associated with a long-term mortality risk comparable to or exceeding that of established risk factors including hypertension, diabetes, smoking, and obesity.”
Mandsager et al., JAMA Network Open, 2018 |
The relationship is not just binary fit vs. unfit. It follows a dose-response curve: every meaningful increase in VO2 max reduces mortality risk, and the improvements at the lower end of the fitness spectrum are the most dramatic.
Researchers from the Cleveland Clinic analyzed data from patients referred for exercise testing and found that going from “low” to “below average” fitness was associated with a greater mortality benefit than any medication we can currently prescribe. Moving from the bottom 25% to the next quartile of fitness reduces all-cause mortality risk by approximately 50%.
The mechanism is not a mystery. Higher VO2 max is associated with:
- Greater stroke volume — your heart pumps more blood per beat, reducing overall cardiac stress
- Lower resting heart rate — a sign of cardiovascular efficiency
- Improved insulin sensitivity — directly reducing metabolic disease risk
- Lower inflammatory markers — chronic inflammation is a primary driver of accelerated aging
- Better mitochondrial density in muscle cells — the same mitochondria that power cellular repair and cognitive function
- Reduced visceral fat accumulation — the metabolically active fat that drives cardiovascular and cancer risk
In longevity medicine, we think about VO2 max not just as a fitness metric but as a proxy for the health of the entire cardiovascular and metabolic system. When we see a patient in their 50s with a VO2 max in the top quartile for their age, we are looking at a fundamentally different health outcome than someone in the bottom quartile regardless of what their annual physical showed.
What Is a Good VO2 Max Score?
VO2 max naturally declines with age approximately 10% per decade after the age of 25 in sedentary individuals, and about half that rate in those who remain active. Age and sex both influence what constitutes a “good” score, so context matters.
As a general clinical framework, here is how I think about VO2 max scores in my patients (mL/kg/min):
| Age 30-39 | Age 40-49 | Age 50-59 | Age 60-69 | Age 70+ | |
| Elite (Top 2.5%) | 55+ | 51+ | 45+ | 41+ | 37+ |
| Superior | 52-54 | 48-50 | 43-44 | 38-40 | 35-36 |
| Excellent | 46-51 | 42-47 | 38-42 | 34-37 | 31-34 |
| Good | 42-45 | 38-41 | 34-37 | 30-33 | 26-30 |
| Average | 38-41 | 34-37 | 30-33 | 26-29 | 22-25 |
| Below Average | 34-37 | 30-33 | 26-29 | 22-25 | 20-21 |
| Low | <34 | <30 | <26 | <22 | <20 |
Approximate norms for males. Female norms are approximately 15–20% lower. Source: ACSM Guidelines for Exercise Testing and Prescription.
When setting VO₂ max targets in our precision longevity program, we don’t aim for “average for your age.” Average often reflects the trajectory we’re trying to avoid. Instead, we aim to build the aerobic capacity of someone 20 years younger, creating a VO₂ max reserve that helps preserve independence, resilience, and physical freedom as aging naturally lowers cardiorespiratory fitness.
How Is VO2 Max Tested?
The gold standard for VO2 max measurement is a maximal cardiopulmonary exercise test (CPET) performed on a treadmill or cycle ergometer while connected to a metabolic cart that measures the oxygen you inhale and the carbon dioxide you exhale in real time. As exercise intensity increases, your oxygen consumption rises until it plateaus even as effort continues. That plateau is your VO2 max.
At Aeternitas, VO2 max testing is conducted by a clinical exercise physiologist and interpreted by your physician in the context of your full cardiovascular profile not in isolation. We look at not just the peak number, but how you get there: your ventilatory threshold (the point at which your breathing pattern changes), your heart rate response, and your recovery kinetics. Each of these tells us something distinct about your cardiovascular system.
Sub-maximal estimates fitness trackers, smartwatch algorithms, and step-test formulas can be useful for tracking trends, but they carry significant error margins, sometimes as wide as 10–15 mL/kg/min. For clinical decision-making in a precision medicine context, we use the direct measurement.
How to Improve Your VO2 Max
This is where the picture gets genuinely encouraging: VO2 max is highly responsive to training, particularly in individuals who are currently sedentary or moderately active. The less fit you are, the more rapidly you can improve.
The two training modalities with the strongest evidence for improving VO2 max are:
-
Zone 2 Training — The Foundation
Zone 2 refers to sustained aerobic exercise at an intensity where you can still hold a conversation but are working at a meaningful pace roughly 60–70% of maximum heart rate, or just below your first ventilatory threshold. Think: brisk walking, easy cycling, light jogging.
Zone 2 training builds mitochondrial density and fat oxidation capacity the metabolic machinery that underpins long-term aerobic fitness. The evidence, championed in recent years by researchers like Dr. Iñigo San Millán at the University of Colorado, suggests that the majority of endurance training should occur in this zone for longevity-focused athletes.
For most of my patients, the practical target is 3–4 hours of Zone 2 activity per week, accumulated in sessions of 45–90 minutes.
-
High-Intensity Interval Training (HIIT) The Accelerator
HIIT involves short bursts of near-maximal effort followed by recovery periods. Intervals of 3–8 minutes at intensities above the second ventilatory threshold (VO2 max intervals) have the strongest evidence for directly driving VO2 max upward.
A protocol well-supported by research: 4 x 4-minute intervals at approximately 90–95% of maximum heart rate, with 3-minute active recovery between intervals, 2–3 times per week. This is demanding. It requires a baseline level of cardiovascular conditioning and should be introduced progressively.
At Aeternitas, exercise prescriptions are designed by our exercise physiologist and calibrated to your baseline VO2 max, your cardiovascular risk profile, and your schedule because a plan you cannot sustain is not a plan.
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What Else Moves the Needle
- Strength training: Building lean muscle mass improves oxygen extraction efficiency and metabolic health both of which support VO2 max gains.
- Sleep: Growth hormone, released primarily during deep sleep, is critical for cardiovascular adaptation to training. Poor sleep limits your response to exercise.
- Nutrition: Adequate protein (to support muscle adaptation), carbohydrate timing around training, and anti-inflammatory dietary patterns all influence training recovery and adaptation speed.
- Consistency over intensity: The single biggest driver of VO2 max improvement is showing up consistently over months and years not any single heroic training block.
VO2 Max as Part of a Comprehensive Longevity Evaluation
Knowing your VO2 max is valuable. Knowing your VO2 max in the context of your coronary artery calcium score, your DEXA body composition, your advanced lipid panel, your metabolic markers, and your neurocognitive baseline is transformative. It changes the conversation from “here is a number” to “here is what this number means for your specific risk profile, and here is the targeted plan to move it.”
That is the model we have built at Aeternitas. On your evaluation day, VO2 max testing is one component of a coordinated assessment designed to establish a true biological baseline across every major system cardiovascular, metabolic, oncologic, cognitive, and structural. Your physician then leads a multidisciplinary team to translate those findings into a written plan with priorities, targets, and accountability.
If you have never had your VO2 max tested and most people reading this have not I would encourage you to change that. It is, in my experience, one of the most motivating data points a patient can receive. When you understand precisely where you stand and what the evidence says about where you could be, the path forward becomes unusually clear.
Frequently Asked Questions About VO2 Max
Is VO2 max the same as cardiovascular fitness?
VO2 max is the most precise quantitative measure of cardiovascular (cardiorespiratory) fitness available. The two terms are often used interchangeably, but VO2 max is the specific number that makes fitness comparable across individuals and trackable over time.
At what age does VO2 max start to decline?
VO2 max begins declining gradually in your late 20s and accelerates through the 30s and 40s. Sedentary individuals lose approximately 10% per decade; physically active people can reduce that rate to 5% or less. The good news: the decline is not fixed. Training can partially reverse it at any age.
Can a smartwatch accurately measure VO2 max?
Consumer devices estimate VO2 max using algorithms based on heart rate and GPS data. These estimates can be useful for tracking relative changes over time in the same individual, but they carry error margins of 10–15 mL/kg/min or more. For clinical decision-making and precise prescription, a direct laboratory measurement is required.
How long does it take to meaningfully improve VO2 max?
With consistent, well-structured training, meaningful improvements are typically seen within 8–12 weeks. Sedentary individuals can see 15–20% gains within 3–6 months of progressive training. Gains continue to accrue over years.
Where can I get a VO2 max test in Charlotte, NC?
Aeternitas Health offers clinically supervised VO2 max testing as part of our comprehensive evaluation day in Charlotte, NC. Testing is conducted by a clinical exercise physiologist and interpreted by your physician in the context of your complete health profile. To learn more, explore membership options here.
| Know Your Number. Own Your Future.
VO2 max testing is part of every Aeternitas evaluation day. A single coordinated visit establishes your true baseline — and a physician-led plan to build from it. |
About the Author
Dr. Corey Helton, MD is the Founder of Aeternitas Health, a physician-led longevity and precision medicine practice in Charlotte, NC. Dr. Helton founded Aeternitas to practice the kind of medicine he believes patients deserve — rigorous, proactive, and deeply personalized — before disease appears. Aeternitas is a direct-pay practice with a deliberately limited membership panel. Learn more about Aeternitas Health.
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- VO2 Max Improvement Plan for Adults Over 40: A Physician-Designed Protocol
Ready to apply these insights to your own health? Schedule a physician consultation at Aeternitas Health in Charlotte, NC.
