VO2 Max by Age: What's a Good Score (and Why It Predicts How Long You'll Live)

If you could pick one number to know about your physiology, it should probably be your VO2 max. Not your weight, not your body fat, not your bench press. VO2 max — the maximum amount of oxygen your body can use per minute — is one of the most powerful single indicators of how your cardiovascular system, your muscles, and your metabolism are actually performing.

And it predicts something most other fitness numbers don't: how long you're likely to live, and how well you'll function in your last decades.

What VO2 max actually is

VO2 max is measured in milliliters of oxygen per kilogram of body weight per minute (ml/kg/min). It represents the upper ceiling of your aerobic engine — the most oxygen your heart can pump, your lungs can extract, your blood can carry, and your mitochondria can use, all at once, when you're working as hard as physically possible.

That number is governed by an integrated system: stroke volume, cardiac output, hemoglobin, capillary density, mitochondrial mass and efficiency, and your skeletal muscle's ability to extract oxygen. Improve any of those and your VO2 max goes up. Let any of them decline and it goes down. It's effectively a fitness score for your entire cardiovascular and metabolic system.

The mortality connection

In 2018, a landmark study published in JAMA Network Open followed over 122,000 patients undergoing exercise treadmill testing. The researchers found a graded, dose-dependent relationship between cardiorespiratory fitness and survival. The least-fit group had 5.04 times the mortality risk of the most-fit group. Their conclusion was direct: low fitness was associated with greater mortality risk than smoking, diabetes, or coronary artery disease.

That's not a typo. Being out of shape — measured by VO2 max — was a worse risk factor than smoking. And the relationship was continuous: every step up in fitness lowered risk. There was no upper limit where additional fitness stopped helping.

This is why longevity researchers like Peter Attia have argued that VO2 max should be treated as one of the most important biomarkers of healthspan. A 50-year-old with a VO2 max in the top quartile for their age is functionally decades younger, cardiovascularly, than a 50-year-old in the bottom quartile.

VO2 max charts by age

Here are research-based VO2 max ranges in ml/kg/min, drawn from standardized fitness norms (ACSM, Cooper Institute). Use these as a starting reference, not gospel — methodology and population matter.

Men

Women

The number that actually matters

Don't fixate on hitting "elite." The mortality data shows the biggest gains come from moving out of "poor" and into "good" — that's where the all-cause mortality curve flattens dramatically. A 50-year-old man going from a VO2 max of 25 to 35 cuts their mortality risk roughly in half. Going from 35 to 45 helps further, but the curve is less steep.

Translation: if you're below average for your age, that's the most important fitness intervention you'll ever make. If you're already "good," pushing toward "excellent" is gravy on top of healthspan.

How to actually improve VO2 max

VO2 max responds to two very specific kinds of training, used together:

1. Zone 2 (the boring engine work)

Zone 2 is steady-state aerobic work at an intensity where you can still hold a conversation but it's clearly an effort — typically 60–70% of max heart rate. This is where mitochondrial density, capillary density, and fat-oxidation capacity are built. It's the foundation of the engine.

For most people: 3–4 sessions per week, 45–60 minutes each. Bike, rower, incline walk, easy run. The effort feels almost too easy. Stick with it for 12 weeks and your VO2 max will move.

2. High-intensity intervals (the ceiling work)

Once the base is built, intervals raise the ceiling. Classic protocols: 4×4 minutes hard with 3 minutes easy between, or 30/30s (30 seconds hard, 30 seconds easy, repeat for 10–20 minutes). One to two sessions per week is enough. More than that and you'll fry your nervous system without additional benefit.

3. Strength training underneath all of it

VO2 max is per-kilogram. Carrying around poorly-conditioned mass tanks the ratio. Strength training preserves and builds lean mass, which directly supports cardiac output and oxygen utilization. 2–3 strength sessions per week alongside the cardio work is the sweet spot for most adults.

Why smartwatch numbers aren't enough

Apple Watch, Garmin, and Whoop estimate VO2 max from heart rate and pace using regression equations. They're useful for trend tracking — if your watch number goes up, you probably did improve — but the absolute number is typically off by 10–15% in either direction. That's the difference between "average" and "excellent" on the chart.

The only way to get a real number is a metabolic cart VO2 max test: you wear a mask while exercising, and the system directly measures the oxygen you consume and the CO₂ you produce. The test takes 12–20 minutes, ramps to maximum effort, and gives you not just VO2 max but your true Zone 2 heart rate, your lactate threshold, and your fat/carb crossover point.

Those last three are arguably more useful than VO2 max itself, because they tell you exactly where to train.

The bottom line

VO2 max is the closest thing we have to a single number that captures cardiovascular health, metabolic function, and longevity potential. The research is clear: low fitness is one of the most dangerous things you can carry into your 50s, 60s, and 70s — more dangerous than smoking, by some measures.

The good news is that VO2 max responds to training at every age. Most untrained adults can improve 15–25% in 6–12 months with the right structure. The first step is knowing where you actually stand — not what your watch guesses, but a real measurement.

You can book a metabolic-cart VO2 max test at our Las Vegas facility, or pair it with our full assessment program to get DEXA, bloodwork, and a movement screen at the same time.