Before you can calculate your fitness age, you'll need to determine your VO2max. This measures how efficiently your body processes oxygen and is a great indicator of cardiovascular endurance.
While, generally speaking, it is best not to compare yourself to others, in order to determine your fitness age you’ll need to do just that. Your fitness age is dependent upon the averages for your age group.
“If your VO2max is below average for your age group, then your fitness age is older than your actual age. But if you compare well, you can actually turn back the clock to a younger fitness age. That means a 50-year-old man conceivably could have a fitness age between 30 and 75, depending on his VO2max.”
via "What's Your Fitness Age?" in The New York Times
Determining your fitness age is worthwhile because of the implications of what physical fitness means for your future. A 2014 study published in Medicine & Science in Sports & Exercise found fitness age to be a significant predictor of life expectancy.
The study used data from 55,000 adults who had filled out lengthy health surveys dating back to the 1980’s. Researchers were able to approximate each volunteer’s fitness age based on how they answered the survey questions. The next morbid but necessary step was to check the death records.
The results were shocking. They found that fitness age may be a better predictor of longevity than even more well-known risk factors like obesity, high blood pressure, and smoking. Volunteers with an estimated VO2max 15% or more below the average for their age had an 82% higher risk of premature death. With a VO2max below the average, this means that their fitness age was considerably older than their chronological age.
Since you probably don’t know your own VO2max or the averages for your age off hand, you can take this short quiz to determine your fitness age.
If the results aren’t exactly what you hoped for, don’t panic.