What is my fitness age? How it is calculated, and how to lower it

A fitness age is the age at which your measured fitness would be average. Calendar 44 with a fitness age of 38 means your engine, frame and base test like a typical 38-year-old's. It is a marketing device and a genuinely useful one, if you know what is inside it.

Where the idea comes from

The Norwegian HUNT study built a fitness-age calculator from VO₂max measured in thousands of adults, then showed that estimated fitness age predicted mortality. Since then every serious version has added strength and functional tests, because aerobic capacity alone misses the muscle and balance failures that dominate later life.

What the Vital age is built from

PeakVital uses three tests: a VO₂max estimate, a timed dead hang, and a 30-second sit-to-stand. Each becomes a percentile for your age and sex. The three percentiles are combined and mapped back to the age at which that combined score would be the median. Younger than the calendar is the goal; the trend every six weeks is the point.

The three levers

• Aerobic base. Two to three easy sessions a week in your lower zones, plus one hard one, moves VO₂max within eight weeks.
• Strength. Two full-body sessions a week move grip and leg power quickly, especially from a low start.
• Consistency. The tests reward the person who trained every week, not the person who trained hard occasionally.

What it does not tell you

A fitness age is not a diagnosis and not a life expectancy. It says nothing about your blood work, your joints or your mind. It says one true thing: how your body performs on three tasks that predict a lot, relative to people your age, and whether that is moving in the right direction.