Your chronological age only tells you how many years you’ve lived on this earth. Depending upon how you’ve spent those years, you may be considerably younger or older from a health and fitness perspective. Researchers at the Norwegian University of Science and Technology in Trondheim have coined the phrase “fitness age” to describe how young or old a person is from a fitness perspective.
This group of researchers spent years studying the relationship between physical fitness and wellness and determined the best measure of how old a person is from a fitness perspective is their aerobic capacity or V02 max. V02 max is a measure of the maximal amount of oxygen your body can deliver to the tissues that need it during exercise. Unfortunately, unlike blood pressure or heart rate, it’s not so easy to measure V02 max. As a result, most people have no idea what their V02 max is.
Measuring Aerobic Capacity
A number of protocols are available for measuring V02 max. With one such protocol you walk or run on a treadmill while wearing a mask. The mask collects the oxygen and carbon dioxide you breathe in and out during exercise so it can be measured. As you run or walk on the treadmill, the grade and speed of the treadmill is gradually increased until you have to stop exercising due to exhaustion. The point at which oxygen consumption reaches a peak and plateaus as the exercise intensity increases is V02 max. At this point, your body can’t increase delivery oxygen to tissues and exercising muscles any faster.
There is a less accurate way to measure your aerobic capacity at home using the run/walk test. You run or walk for 12 minutes and record how many meters you cover during that time. Plug the results into an online calculator to get a rough estimate of your V02 max.
An Alternative to Measuring V02 Max
To get around the problem of measuring V02 max when determining fitness age, the Norwegian researchers looked at a variety of health and fitness measurements like resting heart rate and waist size to see if they could be used to predict a person’s V02 max. They compared a variety of parameters to the results of treadmill testing to see what combination of factors was most predictive of a person’s V02 max. Based on this, they developed a fitness age calculator, available online. This calculator gives an estimate of fitness age based on parameters like age, gender, waist circumference, and exercise habits.
At first, it didn’t appear a person’s fitness age, or V02 max, was predictive of longevity but a subsequent study that looked at estimated V02 max among 55,000 Norwegians did find a link between V02 max and longevity. Those with an estimated V02 max of in the lower 15% for their age had an 82% greater risk of premature mortality. That’s significant!
Using a fitness age calculator online, you can calculate your own fitness age without having your V02 max measured.
How Much Can You Improve Your V02 max?
Your aerobic capacity or V02 max is partially determined by genetics. Just as many traits are inherited and tend to run in families, aerobic capacity has a genetic component. Body composition and gender are other factors that influence V02 max.
Women have V02 max values on average that are 15 to 30% lower than male values, although body composition accounts for a portion of this. Males have more muscle mass. This gives men a greater ability to deliver oxygen. Men also have a higher hemoglobin level relative to women. Higher hemoglobin allows more oxygen to be carried in the blood to tissues.
Age also affects V02 max – no surprise here. V02 max declines about 1% per year after the age of 25. Exercise training can slow down the decline in V02 max or aerobic capacity that happens with age.
How much can you reasonably expect to increase your V02 max through training? For the average person, between 15% and 20%, although some people can make greater improvements than this. People vary in the degree to which they respond to aerobic training.
Is High-Intensity Training Better?
A small percentage of the population who are exercise “non-responders” experience little or no improvement in aerobic capacity despite training. Don’t let that discourage you. Most people improve with training and even those who don’t enjoy the other health benefits exercise offers. Some research suggests that even non-responders can improve their aerobic capacity through high-intensity interval training.
Research also suggests high-intensity exercise is better overall for increasing V02 max than moderate-intensity cardiovascular exercise. Exercising at near maximal intensity for short periods of time using intervals leads to the greatest increase in V02 max, based on a study published in Medicine and Science in Sports and Exercise.
The Bottom Line?
Based on new research, your V02 max is the best indicator of your fitness age and a better indicator of your overall health and fitness than your chronological age. If you’re 50 years old and have a V02 max of a 25-year-old, your fitness age is 25.
Should you really place so much value in a single measurement of aerobic capacity? A number of studies show a link between V02 max and longevity even among people who are overweight. Aerobic capacity is a relatively good indicator of how “robust” your heart, lungs and circulatory system are and that’s an indirect marker for health. Fortunately, you have the capacity through exercise training to improve your aerobic capacity and lower your fitness age.
In reality, V02 max probably shouldn’t be the only factor used to judge how youthful a person is from a health and fitness perspective. You can have good aerobic capacity due to genetics and years of doing endurance exercise but you may lack muscle strength and have less than optimal bone density because you’ve never focused on resistance training. You lose muscle and bone mass with age. This increases the risk of mortality from falls and fractures. That’s why it’s important to have a balanced approach to working out – to enhance aerobic capabilities and preserve strength and lean body mass. All of these factors are important for health.
The New York Times. “What’s Your Fitness Age?” October 2014.
Exercise Physiology: Theory and Application to Fitness and Performance. Seventh Edition. Powers and Howley. (20090
PLOS One. “VO2max Trainability and High-Intensity Interval Training in Humans: A Meta-Analysis” (September 2013)
Med Sci Sports Exerc. 2008;40(7):1336-1343.
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