In This Story
In This Story
Key Takeaways
- VO2 max is one of the stronger predictors of all-cause mortality among commonly measured health metrics, in some analyses ahead of smoking status or diabetes.
- It's a downstream marker of aerobic fitness, not a lever to pull directly — it improves through consistent training, not targeted interventions.
- Wearable estimates are useful as a trend indicator over time but not precise as an absolute number, especially at the fitness extremes.
VO2 max measures the maximum rate at which your body can consume oxygen during intense exercise — a reasonably good proxy for aerobic fitness, and one that's become a headline metric on most fitness watches over the past few years.
Why it correlates with longevity
Large studies have found VO2 max to be one of the stronger predictors of all-cause mortality among commonly measured health metrics — in some analyses, a bigger factor than smoking status or diabetes. That's a striking finding, and it's driven considerable interest in the number as a target to optimize directly.
It's worth being precise about what that means, though: VO2 max is a strong marker of overall cardiovascular and metabolic health, not a lever you pull in isolation. It improves as a downstream effect of consistent aerobic training, not through interventions that target it specifically.
The accuracy caveat
Wearable-estimated VO2 max is a rough approximation, generally accurate as a trend indicator over time but not precise as an absolute number, particularly for very fit or very unfit users at either end of the range. Treat the trend line as useful information, and the single number with some skepticism.
How to actually improve it
VO2 max improves through a mix of Zone 2 base training and periodic higher-intensity intervals — there's no shortcut that bypasses consistent aerobic work. Most people see measurable improvement within eight to twelve weeks of structured training, with gains continuing, though at a slower rate, for months after.
Frequently Asked
What is considered a good VO2 max?
"Good" varies substantially by age and sex, since VO2 max naturally declines with age. Rather than comparing to a fixed number, tracking your own trend over months is more useful than chasing a specific absolute value.
How accurate are smartwatch VO2 max estimates?
Reasonably accurate as a trend indicator over weeks and months, but less precise as an absolute number — particularly for people at either the very fit or very unfit end of the range, where estimation algorithms tend to be less reliable.
Sources
- Large-cohort research comparing cardiorespiratory fitness to other mortality risk factors
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