09/06/2026
Your smartwatch gives you a VO₂ max score, but do you know what that number actually means?
A VO₂ max of 40 could be excellent for one person and below average for another. That's because VO₂ max should always be interpreted based on your age and s*x.
Here's a general idea of what happens over time:
📈 In your 20s, a higher VO₂ max is expected because your cardiovascular system is typically at its peak.
📉 After your mid-20s, VO₂ max naturally declines by about 1% per year (roughly 10% per decade) if you're sedentary.
💪 The good news? Regular aerobic training can significantly slow that decline, helping you maintain your fitness, endurance, and overall health as you age.
It's also important to remember that VO₂ max is more than a performance metric. Research has consistently shown it's one of the strongest indicators of cardiovascular fitness and long-term health. Improving your VO₂ max can mean:
- Better endurance during exercise
- Improved heart and lung function
- More efficient oxygen delivery to your muscles
- Greater independence and quality of life as you age
One thing to keep in mind: most smartwatches don't actually measure VO₂ max. They estimate it using factors like heart rate, pace, and movement. While they're excellent for tracking trends over time, the estimate can be several points away from your true physiological value.
If you're making decisions about training, monitoring a health condition, or simply want to understand your fitness with confidence, a clinical metabolic test provides a direct measurement rather than an estimate.
Knowing your number is helpful.
Understanding what that number means for your age is even more valuable.
Follow for more evidence-based insights on metabolic testing, VO₂ max, and the science behind human performance.
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