VO2Max – The Best Predictor of Longevity

For most health metrics, the principle of "just the right amount" applies (known in English as the "Goldilocks principle"). If anything is too low or too high, the risk of disease and mortality increases. For example, when blood pressure is too high, it is a risk factor for heart attack and stroke, but when it is too low, it raises the risk of blood clots and fainting. However, the Goldilocks rule has certain exceptions, and when it comes to longevity, one of the most significant exceptions is maximal aerobic capacity – known as VO2 max.

It has been well established that increasing VO2 max is associated with a steady reduction in the risk of cardiovascular mortality, but importantly, an increase in VO2 max is also linked to a steady reduction in the risk of all-cause mortality at any age.

What is VO2 max?

For any aerobic physical activity to be possible, whether it’s cycling uphill, hiking in the mountains, or walking briskly around your neighborhood, your muscles need a supply of oxygen to generate energy and sustain repeated movements. This can be measured as the ventilatory oxygen rate or VO2, typically expressed in liters per minute or normalized to body weight in ml/kg/min. The maximum amount of oxygen the body can utilize during intense exercise is called VO2 max, and it is generally considered the best indicator of aerobic fitness and cardiorespiratory endurance.

VO2 max is directly related to the body’s ability to deliver oxygen to muscles, which depends heavily on cardiac performance. Cardiac output, in turn, is highly dependent on maximal heart rate, which is known to decline with age. Consequently, the maximal achievable VO2 max also declines with age. While this decline may mean that at age 70 or 80 you will have a lower absolute speed or endurance compared to when you were 30 or 40, within a healthy range we all need a certain minimum aerobic capacity to handle daily activities, such as climbing stairs or carrying groceries.

How is VO2 max measured?

The most precise way to measure VO2 max is in a laboratory setting. In such an environment, the subject is fitted with a heart rate monitor and a tightly sealed mask to measure oxygen consumption and carbon dioxide production (CO2) while the intensity of exercise gradually increases (usually during treadmill running on an incline or cycling on a stationary bike) until exhaustion.

VO2 Master

VO2 Master is a "home" device for measuring VO2 that uses the same approach as laboratory tests and offers a highly accurate option for at-home measurement. This device is mainly intended for people who are highly interested in frequent VO2 monitoring, such as coaches and trainers. If you only plan to test your VO2 max once or twice a year, it is better to find an exercise lab, as the price of the VO2 Master is over $6,000 in the USA, which is about ten times higher than a single lab test. Primarily for this reason, the device is currently intended for professional use. Personally, I see its greatest advantage in its versatility for use in the field across different sports. While in laboratory testing we are usually limited to a treadmill or stationary bike (or, in rare cases, certain ergometers like rowing machines), the VO2 Master can be used in many other sports such as skiing, kayaking, stand-up paddleboarding, and more. Its disadvantage compared to lab testing is that it currently cannot measure exhaled CO2, though work is being done on the next generation of the device to include this feature.

While laboratory testing or VO2 Master are direct methods of measuring VO2 max, these methods are often not easily available or convenient. Although less precise, several other home-based methods can provide a basic estimate of your VO2 max with greater convenience. One of the most precise cycling performance tests requires increasing output on a stationary bike, where each level is maintained for 2.5 minutes. In your case, VO2 max will relate to your maximal performance. Another popular and relatively precise "field" test is the beep test. Additional VO2 max estimates use the 12-minute run, the 1.5-mile run, or the 1-mile walk (submaximal versions). Several online calculators allow you to enter your results and see where you stand compared to others of your age and gender. All these home methods input your results into an equation that translates your performance into an estimated VO2 max.

There is often a learning curve when performing these tests. To a large extent, this is because during your first attempt at a 12-minute run, you may misjudge the intensity you can sustain for that duration. This could mean you start too fast and exhaust yourself or start too slow and fail to reach your true maximal effort. So, even though it may not be pleasant, if you are doing a maximal test, the best way to get the most accurate assessment is to repeat it several times on different days, as your results will likely get closer to your true maximum with repeated effort.

What evidence links VO2 max and mortality risk?

For decades, we have known from published studies that high cardiorespiratory fitness, as measured by maximal exercise testing, predicts both cardiovascular and all-cause mortality. However, many of these studies divided participants into very broad groups, such as the lowest 20%, middle 40%, and highest 40%. Even within these broad groups, the lowest fitness group had a 69% higher relative risk of all-cause mortality compared to the highest fitness group. In some cases, there was up to a 2.1-fold increase in the relative risk of all-cause mortality, with a similar increase in cardiovascular mortality. Although being in the top 40% for cardiorespiratory fitness is certainly better for your age and gender than being in the bottom 20%, older studies did not clarify whether there was a continuous risk reduction gradient within the highest 40% – in other words, whether further improvements in fitness would continue to reduce risk even for those already above average.

Two very large studies published in recent years answered this question. In 2018, Mandsager and colleagues published a retrospective study of more than 120,000 adults undergoing treadmill stress tests, the standard method for measuring VO2 max. Based on the slope and speed of the treadmill at maximal output, peak energy output was calculated in metabolic equivalents (METs), which can be directly and linearly converted to VO2 max by multiplying by a factor of 3.5. After more than 8.4 years of follow-up, the authors found that those in the top 2.3% (referred to as the "elite" category; see Table 1 below) for VO2 max relative to their age and gender had the lowest risk of cardiovascular and all-cause mortality. Compared to individuals in the elite category, those in the lowest quartile of fitness ("low" group) had more than a fivefold increased risk of all-cause mortality. The likely reason for this dramatic risk reduction is the declining prevalence of comorbidities (such as hypertension or diabetes) that increase cardiovascular risk.

Table 1. Classification of cardiorespiratory fitness by age and gender, reproduced from Mandsager et al.8 VO2 max (estimated VO2 peak) in ml/kg/min oxygen consumption; METS: metabolic equivalents, where 1 MET equals 3.5 ml/kg/min of oxygen consumption. The classification (percentile ranges) is as follows: low (<25th percentile), below average (25th–49th percentile), above average (50th–74th percentile), high (75th–97.6th percentile), and elite (≥97.7th percentile).

The second-best physically prepared group (75th to 97.6th percentile – referred to as "highly fit") had a 29% higher risk of all-cause mortality compared to the absolute elite. The difference in risk between these two fitness levels was statistically significant only in individuals older than 70. However, this does not mean that higher fitness levels at a younger age provide no benefits! The lack of statistical significance in younger age groups in this study is more likely due to the fact that both groups of physically fit young individuals had a lower probability of dying during the limited follow-up period (lasting less than ten years). The overall number of deaths was therefore not high enough for differences between groups to appear.

To understand the enormous impact of low VO2 max on mortality risk, it is enough to look at how this relationship compares to other predictors of all-cause mortality. From the data in Figure 1, it is entirely clear that being unfit has a much greater impact on life expectancy than comorbidities such as hypertension (high blood pressure), diabetes, ischemic heart disease, or even smoking.

Figure 1. Adjusted hazard ratios (HR) for comorbidities and fitness groups. Error bars indicate 95% confidence intervals. The classification of fitness groups based on cardiorespiratory fitness is defined in Table 1. Figure adapted from Mandsager et al.8

Such a large-scale study with significant findings is compelling on its own, but this finding was further confirmed by an even larger study published in 2022 by Kokkinos and colleagues.8 In this study (non-overlapping with the Mandsager study population), VO2 max was also estimated from peak METs achieved during a standardized treadmill test, this time in more than 750,000 subjects followed for a median of 10.2 years. Across all age groups (including those aged 80 to 95), the least fit group – with VO2 max in the 20th percentile – had more than a fourfold increase in all-cause mortality risk compared to the extremely fit (≥98th percentile), and this trend persisted even when stratified by race and sex.

In line with the findings of Mandsager and colleagues, Kokkinos and colleagues also found that comorbidities – including smoking, diabetes, and cancer – increased all-cause mortality risk less than being sedentary or below the 80th percentile in cardiorespiratory fitness. Remarkably, even age was a worse predictor of all-cause mortality than VO2 max (see Figure 2). Let that sink in: having poor cardiovascular fitness is more strongly associated with mortality risk than being old. Unlike unchangeable advancing age, we have a certain degree of control over cardiorespiratory fitness through aerobic exercise. Even if you cannot realistically achieve the highest category of fitness for your age, improving from the 20th to the 60th percentile will result in approximately a 50% reduction in the risk of all-cause mortality. In short, if you want to live longer, the key is regular aerobic exercise.

Figure 2. Adjusted hazard ratios (HR) for comorbidities (in order: Chronic Kidney Disease, Smoking, Diabetes, Atrial Fibrillation, Cancer [all types], Cardiovascular Disease, Hypertension, Age, BMI) and across fitness groups. Error bars indicate 95% confidence intervals. Fitness groups are classified by cardiorespiratory fitness percentiles: 20th percentile (Least Fit), 40th percentile (Low), 60th percentile (Moderate), 80th percentile (Fit), 97th percentile (High), and ≥98th percentile (Extremely Fit). Adapted from Kokkinos et al.9

Is the reduced mortality risk linked only to cardiovascular causes?

The connection between lower cardiovascular mortality and VO2 max may seem logical, but the effect of VO2 max on all-cause mortality clearly goes beyond just the heart. Regular exercise that increases VO2 max leads to physiological adaptations that enhance the body’s ability to utilize oxygen for energy in stressful conditions. While VO2 max is measured during exercise, a significant amount of energy is also needed for immune system responses to illness. The higher your VO2 max, the greater your energy reserves for fighting pathogens or moderating inflammatory reactions. This may contribute to lower mortality, as people with the highest VO2 max are less likely to experience complications during intensive treatments, viral infections, or surgeries.

Why is VO2 max such a reliable indicator?

VO2 max is a uniquely strong predictor of all-cause mortality, likely because it integrates physical fitness and aerobic workload into one number. Unlike questionnaires capturing physical activity levels (which are prone to subjective error) or measurements of resting blood pressure and heart rate (which can be influenced by hydration or anxiety), VO2 max cannot be “faked.” Achieving a high VO2 max is only possible through long-term intensive aerobic activity that increases mitochondrial density in the muscles. Short-term training before a test won’t affect it.

VO2 max reflects body composition, but changing body weight alone has no direct effect. Individuals with high VO2 max tend to have lower fat mass, but the percentage or amount of body fat itself is not a strong predictor of maximal oxygen consumption.

Although it’s impossible to drastically change VO2 max within days, targeted training can significantly increase low values relatively quickly. Up to 12 weeks of cycling at 70% VO2 max can increase VO2 max by 18–30% in untrained individuals. However, no one moves from the lowest to the highest fitness bands without considerable effort and time.

VO2 max – Goals and Training

Let’s remember that the maximum achievable VO2 max declines with age. Our goal remains to perform daily life activities into advanced age (examples shown in Figures 3 and 4), which requires maintaining well above-average VO2 max values throughout life. Whenever possible, I encourage my patients to aim for the elite VO2 max category by their marginal decade or at least to avoid falling below the levels truly needed for their age.

Figure 3. Decline in maximal oxygen consumption (VO2 max) with increasing age in men. Reproduced from Mandsager et al. and the 2024 Compendium of Physical Activities.8,12

Figure 4. Decline in VO2 max with increasing age in women. Adapted from Mandsager et al. and the 2024 Compendium of Physical Activities.8,12

When you first start exercising (or return after a long break), almost any cardiovascular exercise will begin to increase your VO2 max. That’s why beginners typically start training in Zone 2—or sometimes even Zone 1, depending on their initial fitness level. This helps build consistency and improves exercise tolerance before moving to more intense workouts. After a few months of Zone 2 training, you can begin adding VO2 max sessions to further improve your fitness.

It has been repeatedly shown that the best way to increase VO2 max is through high-intensity interval training (though this doesn’t necessarily mean the "HIIT" classes at your local fitness center). Common interval workouts to raise VO2 max typically consist of 3–8-minute intervals at high intensity, with a 1:1 work-to-rest ratio, repeated 4–5 times.The length and number of intervals, as well as the exercise intensity during recovery, depend on your fitness level. Elite athletes might run a mile in 4 minutes, interspersed with slow jogging, while someone new to interval training might alternate 30 seconds or one minute of running with walking, possibly at higher repetitions.

That said, there is no such thing as a "perfect" VO2 max workout. Studies show that even a single 5-minute interval at VO2 max intensity (especially in untrained individuals) provides a meaningful stimulus for adaptation and can increase VO2 max. If you were to perform six repeated high-intensity 5-minute intervals, you would accumulate over 30 minutes of workload at an intensity much higher than you could probably sustain for a continuous 30-minute effort. The goal of repeated shorter intervals is to accumulate greater total time near VO2 max intensity (or close to it) and thus raise total oxygen consumption within a single workout. This may mean many short intervals or fewer longer ones, and this flexibility can be a useful part of your training as you find what works best for you.

Training Beyond VO2 Max

Given the strong evidence that VO2 max is linked to longer lifespan, many people may be tempted to think that VO2 max intervals are the only necessary form of cardiovascular exercise. However, developing high VO2 max requires not only targeted intervals but also massive volumes of lower-intensity Zone 2 training. There are two main reasons: efficiency and aerobic base. For example, compare an amateur cyclist with a professional. When a professional rides, they are stable on the bike without visible excess movements. Nearly all the energy they generate goes into pushing the pedals and moving forward. By contrast, an amateur often sways side to side, wasting a lot of energy. This efficiency only develops through huge volumes of low-intensity work, where movement patterns are refined. This is important because during high-intensity intervals, it is much harder to focus on maintaining good form.

In addition to improving form, Zone 2 work builds your aerobic base. Aerobic base represents the work (i.e., watts) you can perform at a sustainable effort over longer periods. One of the best ways to estimate if you’re in Zone 2 is by measuring lactate concentration in the blood, aiming to stay below 2 mmol/L, typically between 1.7–1.9 mmol/L. Since lactate testing is impractical for most people, there are other methods to estimate Zone 2. One common approach is using the Maffetone heart rate formula: 180 minus your age = estimated heart rate, which can be adjusted up or down based on your actual fitness and health. Another method for gauging Zone 2 intensity is perceived exertion (RPE – rate of perceived exertion). If you’re training in Zone 2 using RPE, you should be able to pass the “talk test,” meaning you should be able to hold a conversation, and the effort level should feel relatively comfortable. Just because your initial Zone 2 intensity is at a certain level doesn’t mean it stays there forever. With regular training, you’ll be able to perform more work (i.e., generate higher watts or run faster) at the same RPE or heart rate. This increased efficiency shows up as reduced oxygen consumption at a given output, which in turn allows you to reach both higher workloads and higher VO2 max.

Avoid Overtraining

A growing body of evidence also suggests that there is such a thing as “too much” high-intensity exercise, at least within a given time frame. Too much high-intensity training can paradoxically reduce performance—a state known as nonfunctional overreaching (NFO)—when short-term, or it can progress into overtraining syndrome if it persists long-term. Symptoms include persistent fatigue, increased irritability, ongoing stiffness or muscle soreness, decreased performance, inability to maintain training schedules, sleep disturbances, reduced concentration, increased susceptibility to illness and headaches, loss of appetite, and weight loss. While the definitive diagnosis of NFO or overtraining syndrome is difficult due to the broad range of nonspecific symptoms, the key treatment is significantly increasing recovery. This typically requires more rest, reducing exercise intensity, improving sleep quality, nutrition, hydration, and managing stressors outside of training.

Because sleep is one of the most important aspects of recovery, combining objective measures (e.g., resting heart rate [RHR], heart rate variability [HRV]) with subjective markers (e.g., perceived muscle soreness, willingness to train) can help predict the potential “cost” of a workout on a given day. Consistently elevated RHR and decreased HRV compared to your baseline, especially if accompanied by other NFO symptoms, indicate that high-intensity training may be adding significant physical stress and that results from such training should be reconsidered.

To avoid slipping into overtraining, it’s important not to increase intensity or training volume too quickly and to ensure adequate recovery, especially after intense sessions. Overreaching can occur even within a single week, as shown in one study where participants focused solely on interval training but trained an excessive number of days per week. In that study, the number of sessions increased each week: Week 1 (two days with 5×4-minute intervals) and Week 2 (two days with 5×8-minute intervals and one session with 5×4-minute intervals) improved performance, but by Week 3 (three days with 5×8-minute intervals and two days with 5×4-minute intervals), performance declined. Noticeable performance drops were also associated with mitochondrial dysfunction and reduced glucose tolerance. Completing most cardiovascular training at lower intensities creates less physiological stress on the body, enabling adequate recovery after fewer highly intense sessions.

In Conclusion

Current evidence suggests that the most effective way to extend lifespan and healthspan is regular aerobic activity over long periods (essentially for life), even if you never reach the highest possible VO2 max. Although absolute maximum aerobic capacity declines with age, targeted and consistent training can provide the energy reserves needed to manage temporary physiological stress from illness or enable participation in the activities you enjoy. This ability to engage with others you love is, after all, what defines quality of life—especially in later years.

* Comorbidity is another illness or disorder that occurs simultaneously with the monitored or described disease/disorder.

** Predictor in medical texts refers to a laboratory finding (or generally another description of the patient’s current state) that can, with a certain probability, “predict” another event, disease, or similar outcome.

Sources:

• https://peterattiamd.com/all-things-vo2-max/

• Hawley JA, Noakes TD. Peak power output predicts maximal oxygen uptake and performance time in trained cyclists. Eur J Appl Physiol Occup Physiol. 1992;65(1):79-83. doi:10.1007/BF01466278

• Cooper KH. A means of assessing maximal oxygen intake. Correlation between field and treadmill testing. JAMA. 1968;203(3):201-204. https://www.ncbi.nlm.nih.gov/pubmed/5694044

• Weiglein L, Herrick J, Kirk S, Kirk EP. The 1-mile walk test is a valid predictor of VO(2max) and is a reliable alternative fitness test to the 1.5-mile run in U.S. Air Force males. Mil Med. 2011;176(6):669-673. doi:10.7205/milmed-d-10-00444

• Kline GM, Porcari JP, Hintermeister R, et al. Estimation of VO2max from a one-mile track walk, gender, age, and body weight. Med Sci Sports Exerc. 1987;19(3):253-259. https://www.ncbi.nlm.nih.gov/pubmed/3600239

• Sui X, Laditka JN, Hardin JW, Blair SN. Estimated functional capacity predicts mortality in older adults. J Am Geriatr Soc. 2007;55(12):1940-1947. doi:10.1111/j.1532-5415.2007.01455.x

• Blair SN, Kampert JB, Kohl HW 3rd, et al. Influences of cardiorespiratory fitness and other precursors on cardiovascular disease and all-cause mortality in men and women. JAMA. 1996;276(3):205-210. https://www.ncbi.nlm.nih.gov/pubmed/8667564

•  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;1(6):e183605. doi:10.1001/jamanetworkopen.2018.3605

• Kokkinos P, Faselis C, Samuel IBH, et al. Cardiorespiratory Fitness and Mortality Risk Across the Spectra of Age, Race, and Sex. J Am Coll Cardiol. 2022;80(6):598-609. doi:10.1016/j.jacc.2022.05.031

• Goran M, Fields DA, Hunter GR, Herd SL, Weinsier RL. Total body fat does not influence maximal aerobic capacity. Int J Obes Relat Metab Disord. 2000;24(7):841-848. doi:10.1038/sj.ijo.0801241

• Murias JM, Kowalchuk JM, Paterson DH. Time course and mechanisms of adaptations in cardiorespiratory fitness with endurance training in older and young men. J Appl Physiol. 2010;108(3):621-627. doi:10.1152/japplphysiol.01152.2009

• Herrmann SD, Willis EA, Ainsworth BE, et al. 2024 Adult Compendium of Physical Activities: A third update of the energy costs of human activities. J Sport Health Sci. 2024;13(1):6-12. doi:10.1016/j.jshs.2023.10.010