It is well known that staying active and being fit is good for our health, but what does it mean to be fit, and how do you measure it? VO2 max is a crucial measure of our aerobic fitness. It reflects the body’s ability to deliver oxygen to muscles during physical activity. More importantly, VO2 max is considered a marker of overall health. 

In this article, we’ll explore why VO2 max is so significant and how it can be improved. We’ll also introduce the NEM approach, which emphasizes taking control of your VO2 max to ensure a healthier life.

What is VO2 max?

VO2 max is the maximum volume of oxygen that our body can absorb and use during exercise. It shows the ability of the body to deliver oxygen to the muscles during exercise.  

Why is VO2 max important?

VO2 max is used to measure aerobic fitness levels and is a good indicator of cardiorespiratory fitness (CRF) and overall health. The higher the amount of oxygen that can be absorbed, the more fit the person is. It is commonly used by trainers to assess the performance of elite athletes and find ways to optimize their results. 

The strong link between cardiorespiratory fitness and the risk of death has been extensively confirmed (1). This connection remains significant regardless of a person’s age, gender, race, or existing health conditions. Furthermore, improved CRF is associated with various advantages for the heart and overall health, such as reduced risks of coronary artery disease, high blood pressure, diabetes, stroke, and even certain types of cancer. It is therefore considered by some as a biomarker of ultimate health and long-term survival, and it has been used not only on athletes but on the general population as well (2).

The role of oxygen in exercising muscles

As mentioned, VO2 max is the maximum amount of oxygen the body can use during intense exercises, such as fast running or cycling (2). It’s the point where the body cannot take in any more oxygen, no matter how hard it is pushing. Muscles need oxygen to function properly. When you breathe in, the air provides oxygen that is carried to the muscles through blood. If there is not enough oxygen, another pathway kicks in, and the muscles get their energy supply without oxygen (anaerobically) to compensate for the deficit. When that happens, the muscles will start to produce lactic acid, which can lead to tiredness and achiness. The body has a system to deliver oxygen to the muscles. When you breathe in, your respiratory system facilitates the exchange of oxygen and carbon dioxide between the alveoli in the lungs and the bloodstream. The heart then pumps oxygen-rich blood to the mitochondria in the muscles. The oxygen moves from the blood into the muscle cells, where it is used to create energy. VO2 max depends on how well the lungs, heart, and muscles can work together during intense exercise (2). Super-fit athletes often have higher VO2 max compared to non-athletes. Also, as people age, their bodies don’t function as efficiently, leading to lower oxygen utilization. This is why usually older people have lower VO2 max compared to younger people.

How is VO2 max measured?

Measuring VO2 max can be done in various ways. Some methods directly measure it, while others indirectly estimate it based on different factors and then correlate it back to VO2 max. Since the VO2 max test depends on one’s fitness level and some tests are very demanding, some of the tests are performed at around 80% of the maximal performance level. These tests, known as submaximal, involve a calculation to determine the VO2 max (3). 

  • Direct measurements of VO2 max

There are different protocols for direct measurement of VO2 max (i.e. Bruce, Balke protocol etc) (3). When directly measured, the test is usually conducted in a controlled environment, such as a medical facility with medical oversight or in a fitness center under the supervision of a certified fitness specialist. 

In the direct measurement method, the individual is connected to a machine, and a mask is worn to monitor oxygen intake and carbon dioxide release. This usually involves running on a treadmill or using a stationary bike. The test continues until the VO2 max is achieved, which is indicated by a plateau in the amount of oxygen consumed. VO2 max is measured in mL per minute and then adjusted for body weight (mL/min/kg) (3).

While this direct measurement method is highly valid and reliable, it can be uncomfortable, costly, and time-consuming (3).

  • Indirect measurements of VO2 max 

Instead of directly measuring VO2 max, there are alternative indirect tests that use mathematical equations to estimate it. These tests are more accessible and less physically demanding, making them particularly useful for individuals who are obese or lead sedentary lifestyles. Two commonly used tests include (3):

  1. 1.5 Mile Run Test: This test involves running 1.5 miles as quickly as possible. The recorded data includes the time it takes for the run and the heart rate.
  2. Cooper Test (12-Minute Run Test): Participants run at their maximum effort for 12 minutes, and the distance covered is recorded. This distance is then used to calculate VO2 max.

It is essential to note that these indirect tests provide estimations of cardiorespiratory fitness and are not as precise as direct VO2 max tests. However, when conducted correctly, they can serve as good indicators of overall performance. Additionally, it is important to monitor trends and improvements in VO2 max over time.

Can we increase VO2 max?

Yes! Although the VO2 max has a significant genetic component and is affected by the aging process, it can improve significantly at any age with regular endurance training by approximately 15– 20% (2). That means that a trained 70-year-old potentially can be as fit as an untrained 50-year-old (Figure 1) (2). Untrained 25-year-olds have a VO2 max of around 42 mL/kg/min, and this declines to about 21 mL/kg/min by age 75, with men experiencing a greater absolute decline than women (2). Yet, trained adults, even as they age, remain significantly more aerobically fit compared to their untrained peers, which is crucial for lowering disability and mortality risks. To maintain an independent lifestyle and higher survival chances, a VO2 max of at least 17.5 mL/kg/min is necessary. Aging and physical inactivity can negatively affect the body’s oxygen systems and VO2 max. That can be remedied with appropriate exercise programs.

VO2 Max

Figure 1 (adopted from (2)): Age-related decline of VO2 max in endurance trained male (- – – -) and female (……..) athletes, and sedentary control subjects (solid line)

How to increase VO2 max?

High-intensity interval training (HIIT), endurance, and resistance training have significant effects on various aspects of health in healthy adults (2). Within a few weeks, these programs can boost strength, muscle mass, aerobic and anaerobic capacity, and have positive impacts on the cardiovascular and respiratory systems. 

  • HIIT

HIIT is a form of interval exercise that involves repeated cycles of high-intensity movements, which elevate the heart rate to at least 80% of the maximum heart rate, followed by brief periods of less intense activities (4).Studies have shown that short-intervals (≤30 s), low-volume (≤5 min) and short-term (≤4 weeks) HIIT represent effective and time-efficient strategies for developing VO2 max, especially for the general population. To maximize the training effects on VO2max, long-interval (≥2 min), high-volume (≥15 min) and moderate to long-term (≥4–12 weeks) HIIT are recommended (5).

  • Resistance training 

Resistance training is one of the best ways to improve muscle mass and endurance. It involves exercising muscles using some form of resistance such as own body weight, weights, or resistance bands. One study showed that just a 6-week resistance training program can increase strength by up to 50% in older sedentary individuals (6). Resistance training activates specific muscle-renewing cells and can also enhance the body’s ability to use oxygen, ultimately improving VO2 max.

  • Endurance training

Endurance training is considered one of the best approaches for improving CRF, leading to increased VO2 max (2). This training helps by improving the heart’s output and the muscle’s ability to extract and use oxygen. Endurance training also enhances capillary supply and increases key enzyme activity in muscles, allowing for better fat usage during exercise and improved exercise tolerance. This ability to tolerate prolonged exercise is essential for daily activities and longer exercise sessions, although VO2 max only represents an upper limit and isn’t the sole factor determining endurance. The capacity to utilize a significant portion of VO2 max is a result of adaptations in skeletal muscles due to consistent exercise.

As with other muscles in the body, the strength and endurance of the body decline with advancing age. Usual endurance exercise training, has been shown to prevent or improve this decline thereby supporting the preservation or improvement of exercise tolerance, and in turn VO2 max (2).


What VO2 max is considered good?- the NEM approach

The NEM approach to VO2 max recognizes that a person’s VO2 max is influenced by their age, gender, and current fitness level. Typically, conventional medical wisdom suggests that if your VO2 max falls within the expected range for your age and gender, you’re considered healthy, and no specific action is required. However, NEM takes a different stance. We acknowledge that VO2 max naturally decreases with age, even among elite athletes. Therefore, we encourage our clients to actively work on improving their VO2 max because there’s no upper limit on how high it can be. We tailor exercise plans for each client, helping them increase their performance. This proactive approach ensures that individuals are better equipped to handle the physical demands of daily life as they get older, allowing them to enjoy a high quality of life even in their later years.

The science of VO2 max reveals that it is an important fitness measurement and it is connected to long-lasting health. The link between CRF, VO2 max, and longevity is well-established. While VO2 max naturally declines with age, it’s not a fixed number. At NEM, we believe there’s no upper limit to how high your VO2 max can be. We advocate a proactive approach, customizing exercise plans to help individuals enhance their fitness and maximize their VO2 max. By doing so, we prepare them for the physical demands of daily life, ensuring they enjoy a high quality of life well into their later years. By understanding the benefits of an optimized VO2 max, our clients experience improved health and fitness levels now, and their efforts will pay off today and later in life. Always perform exercise with a proper warm up and consult a doctor if you have any underlaying conditions.


Silviya Demerzhan, Ph.D.

Chief Scientific Officer, Nordic Executive Medicine
Medical review by: Dr. Mahir Vazda MD


 1. Mandsager K, Harb S, Cremer P, Phelan D, Nissen SE, Jaber W. Association of Cardiorespiratory Fitness With Long-term Mortality Among Adults Undergoing Exercise Treadmill Testing. JAMA Netw Open. 2018 Oct 19;1(6):e183605. 

2. Strasser B, Burtscher M. Survival of the fittest: VO2max, a key predictor of longevity? Front Biosci-Landmark. 2018 Mar 1;23(8):1505–16. 

3. Buttar K, Saboo N. A review: Maximal oxygen uptake (VO2 max) and its  estimation methods. Int J Phys Educ Sports Health. 2019;6:24–32. 

4. Avenue 677 Huntington, Boston, Ma 02115. The Nutrition Source. 2021 [cited 2023 Oct 27]. HIIT (High Intensity Interval Training). Available from:

5. Wen D, Utesch T, Wu J, Robertson S, Liu J, Hu G, et al. Effects of different protocols of high intensity interval training for VO2max improvements in adults: A meta-analysis of randomised controlled trials. J Sci Med Sport. 2019 Aug;22(8):941–7. 

6. Bautmans I, Van Puyvelde K, Mets T. Sarcopenia and Functional Decline: Pathophysiology, Prevention and Therapy. Acta Clin Belg. 2009 Aug 1;64(4):303–16.