VO2 Max: FRIEND Treadmill Reference Table
FitnessNorms reproduces the updated FRIEND treadmill reference standards from Kaminsky et al. 2022. The exact percentile vectors are taken from study coauthor James E. Peterman's public FRIENDanalysis implementation, whose documentation identifies the 2022 edition as the peak-RER-at-least-1.10 standards.
- Outcome: directly measured relative VO2peak in mL/kg/min during treadmill cardiopulmonary exercise testing. The familiar page name says VO2 Max, but the source outcome is peak oxygen uptake.
- Percentiles: P5, P25, P50, P75, and P95 are selected directly from the implementation's 21 published percentile points. No interpolation, smoothing, equation, or unit conversion is applied.
- Age groups: 20-29 through 80-89 are retained exactly. The old 80+ label was broader than the evidence and has been replaced with 80-89.
- Exercise mode: only the treadmill table is displayed. The paper publishes separate cycle-ergometer standards, which are not substituted or pooled here.
- Effort criterion: the selected edition requires peak respiratory exchange ratio of at least 1.10. RER is a source inclusion criterion, not a FitnessNorms calculation.
| Sample layer | n | How it is used |
|---|---|---|
| Full updated FRIEND analysis | 22,379 | Reference-page parent-study n |
| Treadmill tests | 16,278 | Parent pool for treadmill analyses |
| Treadmill tests with peak RER at least 1.10 | Not stated in the public implementation | Displayed percentile table |
The source badge deliberately omits a sample size. Repeating 22,379 would include 6,101 cycle tests that do not contribute to this table, while repeating 16,278 would present the treadmill parent pool as if every test met the stricter RER criterion. The reference page retains n=22,379 and labels it as the full study total.
The trend chart places each closed decade at its conventional midpoint: 25, 35, 45, 55, 65, 75, and 85. These are display coordinates, not observations at one exact age. The chart copies only the source medians and does not fit a decline equation.
FRIEND combines retrospective tests performed from 1968 through March 2021 at 34 US laboratories. The source laboratories varied in equipment, treadmill protocols, stopping decisions, and peak-value averaging. A 2026 ERS technical standard likewise warns that site, equipment, protocol, and analytical heterogeneity limit universal CPET reference ranges. These percentiles are a source-specific distribution, not clinical thresholds.