VO2 max: the overlooked fitness number longevity experts want you tracking
September 27, 2026 · 21 min read
Several guests single out cardiorespiratory fitness, measured as VO2 max, as one of the strongest predictors of lifespan and a pillar alongside strength. It is measurable and trainable at almost any age, which makes it a concrete target rather than vague advice to do more cardio.
The rules, numbers and steps worth keeping in front of you.
- Attia: the least fit quarter versus the top 2.5% is about a fivefold difference in all-cause mortality.
- Attia: moving from the bottom quarter into the 50th to 75th percentile roughly halves the risk.
- Attia's comparison: smoking about 40%, high blood pressure 20 to 25%, type 2 diabetes about 25%.
- Attia: VO2 max declines roughly 8 to 10% per decade.
- Backcast: decide what you want to do at 90, then work out the fitness needed today.
- Attia's pyramid: zone 2 is the base width, VO2 max the height.
- Attia wants three to four hours of zone 2 a week.
- With only three hours, Attia's team splits them: one hour each of zone 2, strength and intervals.
- Wright: four brisk 45-minute walks weekly plus two sprint sessions of 30 seconds hard, four rounds.
- Huberman: at least one 45- to 75-minute zone 2 session and one high-intensity session weekly.
- Huberman: don't stack two hard interval sessions in one day.
- Huberman: after about 10 days without training, brain oxygenation declines significantly.
- Attia's rule: meet basic fitness benchmarks before arguing about supplements or diets.
- Get a doctor's advice before hard intervals or a maximal test if you have heart disease, high blood pressure, joint problems or a long sedentary history.
This is the short form. The full insight has every expert's reasoning, their own words and the sources.