How fitness age is calculated here
This calculator compares your VO2max with the median (50th percentile) treadmill VO2max of people of your sex at each age in the FRIEND registry (Kaminsky et al., Mayo Clinic Proceedings, 2015). Your fitness age is the age at which your value would be the typical value, interpolated between decade mid-points (25, 35 … 75).
Not the NTNU calculator. The Norwegian NTNU (CERG) fitness-age calculator uses a different model built from the HUNT study, so its results will differ. Fitness ages below 25 or above 75 are shown as “under 25” or “over 75”.
FRIEND VO2max percentiles — Men
| Age | 5th | 10th | 25th | 50th | 75th | 90th | 95th |
|---|---|---|---|---|---|---|---|
| 20–29 | 29.0 | 32.1 | 40.1 | 48.0 | 55.2 | 61.8 | 66.3 |
| 30–39 | 27.2 | 30.2 | 35.9 | 42.4 | 49.2 | 56.5 | 59.8 |
| 40–49 | 24.2 | 26.8 | 31.9 | 37.8 | 45.0 | 52.1 | 55.6 |
| 50–59 | 20.9 | 22.8 | 27.1 | 32.6 | 39.7 | 45.6 | 50.7 |
| 60–69 | 17.4 | 19.8 | 23.7 | 28.2 | 34.5 | 40.3 | 43.0 |
| 70–79 | 16.3 | 17.1 | 20.4 | 24.4 | 30.4 | 36.6 | 39.7 |
FRIEND VO2max percentiles — Women
| Age | 5th | 10th | 25th | 50th | 75th | 90th | 95th |
|---|---|---|---|---|---|---|---|
| 20–29 | 21.7 | 23.9 | 30.5 | 37.6 | 44.7 | 51.3 | 56.0 |
| 30–39 | 19.0 | 20.9 | 25.3 | 30.2 | 36.1 | 41.4 | 45.8 |
| 40–49 | 17.0 | 18.8 | 22.1 | 26.7 | 32.4 | 38.4 | 41.7 |
| 50–59 | 16.0 | 17.3 | 19.9 | 23.4 | 27.6 | 32.0 | 35.9 |
| 60–69 | 13.4 | 14.6 | 17.2 | 20.0 | 23.8 | 27.0 | 29.4 |
| 70–79 | 13.1 | 13.6 | 15.6 | 18.3 | 20.8 | 23.1 | 24.1 |
ml/kg/min, cardiopulmonary treadmill tests. Source: Kaminsky LA et al. Reference standards for cardiorespiratory fitness measured with cardiopulmonary exercise testing. Mayo Clin Proc 2015;90(11):1515–23, Table 3.
Why it matters
Cardiorespiratory fitness is one of the strongest predictors of long-term health in large population studies. The encouraging part is that VO2max responds to training at every age: a mix of easy aerobic running and some harder intervals can raise it by several ml/kg/min, which can lower your fitness age by years.
Related: age grading, Zone 2 training, VDOT.
Last reviewed: September 2026 · Health disclaimer