What exactly is VO2 max, and what does it tell us about a person’s overall health and fitness?
VO2 max is the maximum amount of oxygen your body can take in, transport, and utilize during intense exercise.
I like to think of it as a measurement of how effectively three major systems work together: your lungs, heart and circulation, and muscles. Your lungs bring oxygen into the body, your heart and blood vessels deliver it to working muscles, and your muscles use it to produce energy.
VO2 max gives us insight into how efficiently this entire system performs when the body is placed under increasing physical stress.
Why has VO2 max become such an important measurement for cardiovascular health and longevity?
Cardiorespiratory fitness is one of the strongest indicators we have of overall health. Large observational studies have consistently found that people with higher cardiorespiratory fitness have a lower risk of cardiovascular disease and premature death.
That’s why VO2 max shouldn’t be viewed only as an athletic performance number. It is also a measure of health and functional capacity.
It tells us something about how well the body responds when demand increases — whether that means climbing stairs, hiking, running, playing a sport, or maintaining independence as we age.
How is VO2 max tested, and who should consider having it measured?
During a clinical cardiopulmonary exercise test (CPET), a person exercises on a stationary bike or treadmill while wearing a specialized mask or mouthpiece. Equipment measures oxygen consumption and carbon dioxide production breath by breath while heart rate and other physiological measurements are monitored as the workload gradually increases.
Testing can be valuable for someone who wants to establish a baseline fitness level and develop a more structured exercise strategy. Depending on the individual and appropriate medical evaluation, it can also provide useful information for people managing chronic conditions or cardiometabolic risk factors such as obesity, diabetes, and hypertension.
It can also benefit people interested in improving performance in running, cycling, rowing, hiking, or other endurance activities.
What is considered a “good” VO2 max?
I encourage people not to think of their VO2 max simply as “good” or “bad.”
VO2 max varies considerably with age, biological sex, genetics, body size, and training status. It should be compared with appropriate reference values and interpreted within the context of the individual.
Your first measurement is your baseline — not your destiny. The more useful questions are: Where are you today? What are your goals? And what can we do to improve your fitness safely over time?
The objective isn’t necessarily to compete with someone else’s VO2 max. It is to understand your physiology and progressively improve your own health and performance.
Can someone exercise regularly and still have a relatively low VO2 max?
Absolutely. Someone can look physically healthy or exercise regularly and still have cardiorespiratory fitness that is lower than expected for their age and sex.
One possibility is that their exercise routine isn’t structured in a way that sufficiently challenges and develops the aerobic system. But a lower-than-expected result can have many explanations, which is why the entire clinical and exercise context matters.
Rather than viewing the number as a judgment, I view it as information that can help us identify potential limitations and develop a strategy based on the individual’s goals.
Can VO2 max be improved at any age, and what exercise is most effective?
Yes. Cardiorespiratory fitness can improve across the lifespan, although the amount of improvement varies among individuals.
The foundation is consistent aerobic exercise combined with appropriately prescribed higher-intensity interval training when safe and suitable for the individual.
Resistance training also plays an important role in overall physical capacity, metabolic health, strength, and healthy aging.
Measurable improvements in cardiorespiratory fitness can occur within weeks to a few months of consistent, appropriately prescribed training. In practice, two to three months can be a useful interval for evaluating meaningful progress.
The goal, however, shouldn’t be to chase rapid changes in one number. Consistency ultimately matters more than a single intense workout.
How accurate are VO2 max estimates from fitness trackers?
Wearable devices can be extremely useful, but most estimate VO2 max using algorithms that incorporate information such as heart rate, pace, speed, age, sex, and exercise patterns.
They are not directly measuring oxygen consumption.
Clinical exercise testing measures oxygen consumption and carbon dioxide production from respiratory gases as exercise intensity increases, providing a much more direct assessment.
Wearables are still valuable for following trends over time. I think of the two approaches this way: Clinical testing establishes the physiological baseline. Wearable technology helps monitor the journey.
What is your best advice for improving VO2 max?
Train with purpose and intention. Don’t simply exercise harder. Understand where you are starting, identify your strengths and limitations, and progressively challenge your body.
Measure. Understand. Train. Recover. Progress.
Your VO2 max is more than a fitness score. It is one window into how your body responds to physical stress — and, importantly, it is something you can work to improve.
For more information or to schedule an appointment, visit Health 360 Wellness Clinic or call 901.496.6066.
Kaushal Kalra, M.D., MPH, is board-certified in Family Medicine and Obesity Medicine and is a Certified Personal Trainer and Corrective Exercise Specialist. He is the Founder and Medical Director of Health 360° Wellness Clinic in Memphis, where he focuses on metabolic health, chronic disease prevention, medical fitness, and long-term well-being.
