VO₂ max tends to be lower in older age groups, but there is no single “normal” number for every adult of the same age. Reference values depend on who was studied, how oxygen use was measured, whether a treadmill or cycle was used, and how results were grouped.
What an age reference actually shows
An age table describes a population distribution. The median is the middle observed value, not a target everyone should reach. Percentiles show where a measurement falls relative to that sample. They do not diagnose health, explain why the value occurred, or establish a safe training plan.
The updated FRIEND standards included 22,379 cardiopulmonary exercise tests from apparently healthy US adults aged 20–89. The researchers reported values by decade, sex, and treadmill or cycle mode. Median peak oxygen consumption was higher for treadmill tests than cycle tests, and the typical values declined across older decades.
A 2026 European Respiratory Society technical-standard project assembled healthy-participant data from multiple regions but found that differences between sites, equipment, protocols, and averaging methods were too large to support dependable global reference equations. That newer finding reinforces the need to label the current reference as population- and method-specific rather than universal.
Fitness Age Calculator uses the eligible treadmill reference and reports a broad percentile band. It does not claim an exact percentile between published cut points. It also stops at the supported age boundaries instead of extending the curve into ages the dataset did not cover.
Why your device table may look different
A wearable may estimate VO₂ max during outdoor exercise, while a clinic may measure peak oxygen use with respiratory gases. A systematic review of consumer wearables found that exercise-based algorithms had lower average bias than resting-information algorithms, yet individual error remained wide. Device model, algorithm version, activity type, and user population also matter.
That means a watch category and a laboratory reference can disagree without either number being a transcription mistake. Avoid moving a value from one method into a table built for another unless the source explicitly supports that use.
A better way to interpret the number
Use four pieces together:
- the value and unit;
- the test or estimation method;
- the population and protocol behind the comparison;
- uncertainty, including ordinary day-to-day and measurement variation.
For trends, repeat a comparable protocol under similar conditions. A small movement may be noise, especially if the plausible ranges overlap. A larger, sustained change across repeated tests is more informative, though it still does not prove what caused it.
Read what VO₂ max measures, inspect the calculator’s reference methodology, or use the cited one-mile walk estimator if its age range and safety conditions fit.