- VO2 max is the most oxygen your body can use during hard exercise — a top-line fitness marker.
- Higher cardiorespiratory fitness is associated with better long-term health.
- Improve it with a big easy aerobic base plus a little high-intensity work.
- Consistency over months moves it; no single session does.
- Wearable readings are estimates — track your own trend, don't obsess over the number.
VO2 max gets a lot of airtime, and for once the hype points somewhere real. This is the companion to training for your prime — read that for how it fits the bigger picture; read this for what the term actually means.
What VO2 max is
VO2 max is the maximum amount of oxygen your body can take in and use when you're working hard. Think of it as the size of your aerobic engine: the higher it is, the more capacity you have for sustained effort, and the more headroom you have for everyday life. It's the headline measure of cardiorespiratory fitness.
Why it matters for the long game
Beyond sport, cardiorespiratory fitness is one of the strongest, most modifiable markers of long-term health — higher fitness is associated with better outcomes as people age. That's why it's become a longevity talking point. The practical takeaway isn't to chase a number; it's that the work which raises VO2 max — regular aerobic activity — is the same work the Heart Foundation and the Australian activity guidelines already recommend for your heart and overall health.
How to improve it
Two ingredients, in this order:
- A big easy base. Most of your aerobic time should be comfortable — see Zone 2 training. This raises your engine's efficiency without wearing you down.
- A little hard work. Once you have a base, add a modest amount of higher-intensity interval training — short, harder efforts with recovery between — which is particularly effective at lifting VO2 max.
The ratio most people thrive on is mostly easy, a little hard. And the real driver is consistency over months, not any one heroic session. Build gradually, recover well (recovery guide), and let it accrue.
How it's measured
A true VO2 max test is done in a lab with a mask measuring your gas exchange during a graded effort. Most people will only ever see the estimate from a smartwatch or fitness app, which infers it from heart rate and pace. Those estimates are rough — useful for watching your own trend over time, not for precise comparisons between people. Don't let an algorithm's number rule your training.
High-intensity work raises the demand on your heart and body. If you're new to exercise, returning after a break, or have a heart or other health condition, check with your GP before adding hard intervals — and build up gradually. This is general information, not personalised advice.
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Sources
- Heart Foundation — benefits of physical activity and aerobic fitness. heartfoundation.org.au
- healthdirect (Australian Government) — cardiovascular exercise. healthdirect.gov.au
- Australian Government Department of Health — movement guidelines, adults 18–64. health.gov.au