Key points
- VO₂max is one of the cardiorespiratory fitness indicators reflecting the amount of oxygen the body can utilize during intense exercise.
- Low cardiorespiratory fitness is associated with many health outcomes; however, on its own, it is not a diagnosis of disease or a measurement of “biological age.”
- Direct measurement is typically performed via respiratory gas analysis during an exercise test. Watch and treadmill estimates can be useful, but should not be considered equivalent to true measurement.
- VO₂max is influenced by age, sex, genetics, training level, hemoglobin, cardiopulmonary capacity, and muscle function.
What does VO₂max indicate?
VO₂max is the integrated result of oxygen taken in during exercise, transported by the circulatory system, and utilized by working muscles. Therefore, it reflects not only lung capacity, but the combined performance of many steps such as cardiac output, vascular system, hemoglobin, muscle mass, and mitochondrial capacity.
Why is it important for healthy aging?
Cardiorespiratory fitness has demonstrated strong associations with mortality and numerous chronic disease outcomes in large cohorts. A large review of meta-analyses published in 2024 reported that higher fitness levels were associated with lower all-cause mortality and various disease risks. While this association is significant, it should be interpreted alongside age, diseases, blood pressure, lipids, glucose metabolism, and other clinical data in individual risk assessment.
How is VO₂max measured?
Cardiopulmonary exercise testing
The most detailed approach is the cardiopulmonary exercise test (CPET), in which oxygen consumption and carbon dioxide production are measured via respiratory gas analysis under increasing workload on a treadmill or cycle ergometer. The test can provide information not only on a VO₂max value, but also regarding ventilatory and circulatory responses.
Submaximal and estimated measurements
Field tests, running/walking protocols, and certain wearable devices can provide a VO₂max estimate. They may be practical for monitoring; however, the algorithm, device, and test conditions can affect the result. For this reason, rather than directly comparing numbers from different devices, serial measurements using the same method are more meaningful.
What should a “good VO₂max” be?
There is no single universal target. Values vary significantly according to age and sex. In clinical interpretation, not only the absolute number, but the percentile in the reference population, the individual’s activity level, symptoms, and measurement method are taken into account. The goal is not to chase as high a number as possible, but to develop an aerobic capacity that the person can maintain safely.
How can VO₂max be improved?
Regular aerobic exercise, especially moderate-intensity endurance training and controlled interval exercises in appropriate individuals, can increase cardiorespiratory capacity. Resistance exercise, sleep, correcting limiting conditions such as anemia or iron deficiency, smoking cessation, and appropriate treatment of cardiopulmonary diseases can also affect performance.
When should testing be postponed or a physician evaluation be performed?
In cases such as new-onset chest pain, unexplained syncope, significant arrhythmia, uncontrolled hypertension, acute infection, or severe shortness of breath, a medical evaluation is required prior to high-intensity testing.
Our approach at our Bodrum clinic
Rather than using the VO₂max value solely as a “fitness age” label, we evaluate it alongside muscle strength, body composition, blood pressure, metabolic data, sleep, HRV, and the person’s actual daily performance. If serial measurements are to be performed, we prefer comparisons using the same protocol and device as much as possible.
Related content
References
- Lang JJ, et al. Cardiorespiratory fitness is a strong and consistent predictor of morbidity and mortality among adults. Br J Sports Med. 2024. PMID: 38599681.
For the general framework in which measurements such as VO₂max, muscle strength, metabolic health, and sleep are evaluated together, you can review the Healthy Aging and Longevity guide.
Written and medically reviewed by: Dr. Kerem Çağlayan
Last medical review: September 10, 2026
Information: Exercise capacity and goals are planned together with personal health status, current fitness, and clinical evaluation.
