Fitness Tool
Estimate your cardiorespiratory fitness without a lab. Choose a method, enter your numbers, and see where you rank — plus what it means for your longevity.
No running required. Uses your resting heart rate and activity level to estimate VO2 max.
Measure after 5 min lying still
VO2 max — maximal oxygen uptake — is the maximum rate at which your body can consume oxygen during sustained exercise. It is the gold standard measure of cardiorespiratory fitness and one of the most comprehensively studied predictors of long-term health outcomes in medicine. A landmark 2018 study published in JAMA Network Open that followed over 122,000 patients for a median of 8.4 years found that low cardiorespiratory fitness was associated with a higher mortality risk than smoking, diabetes, or coronary artery disease. Improving from low to below-average fitness reduced all-cause mortality by 49% — a larger risk reduction than most pharmaceutical interventions produce.
VO2 max declines approximately 10% per decade after age 30 without specific training, but this decline is dramatically modifiable. Masters athletes who maintain aerobic training into their 60s and 70s can have VO2 max values equivalent to sedentary people 20–30 years younger. The mechanism matters: high VO2 max reflects mitochondrial density, capillary density in muscle tissue, stroke volume of the heart, and oxygen extraction efficiency — all of which are independently associated with reduced cardiovascular disease risk, better metabolic health, and slower biological ageing.
This tool offers two estimation methods. The non-exercise formula uses age, sex, resting heart rate, and physical activity level to estimate VO2 max using the Uth-Sørensen-Overgaard-Pedersen equation, which has been validated against laboratory-measured VO2 max with a standard error of approximately 4–5 ml/kg/min. The Cooper 12-Minute Run Test uses the distance you can cover running at your maximum sustainable pace over 12 minutes; the formula (distance in metres minus 504.9, divided by 44.73) was validated by Dr. Kenneth Cooper against direct oxygen measurement in the 1960s and remains one of the most reliable field tests available.
For context, elite endurance athletes typically have VO2 max values above 70 ml/kg/min for men and 60 ml/kg/min for women. For longevity purposes, research from Peter Attia and others suggests that the goal for most people is to be in the top quartile for their age and sex — above 50 ml/kg/min for men under 40 and above 43 ml/kg/min for women in the same age group. Even reaching the above-average range carries substantial mortality benefits compared to low fitness.
VO2 max responds strongly to specific training stimuli. Zone 2 aerobic training — sustained exercise at 60–70% of maximum heart rate — builds the mitochondrial and capillary infrastructure that underpins VO2 max over months of consistent work. High-intensity interval training (HIIT), particularly Norwegian-style 4x4 intervals at 90–95% maximum heart rate, produces faster VO2 max gains. Research from the Norwegian University of Science and Technology showed that 4 x 4 minutes at 90–95% maximum heart rate, performed twice weekly, improved VO2 max by an average of 7.2% in 8 weeks in sedentary adults. A combination of Zone 2 base building and weekly HIIT sessions is the approach most consistently supported by the literature for maximising VO2 max across age groups.
Go Deeper
Why VO2 max is the single strongest predictor of lifespan — and the training protocols shown to improve it at any age.
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