VO2 Max and Longevity: Should Women Over 40 Know Theirs?

Medically reviewed by our medical team
VO2 max has become a popular topic in longevity conversations. Many smartwatches now display a number, yet most women have never had it measured in a lab.

This article explains what VO2 max measures and why fitness matters for long-term health. It also covers whether you need to know your exact score.

Key Takeaways

• VO2 max reflects how well your body takes in and uses oxygen during hard exercise.
• Higher fitness is linked with lower risk of heart disease and early death.
• VO2 max tends to decline with age, but the rate varies from person to person.
• Smartwatch numbers are estimates, so trends matter more than a single score.
• Fitness can improve after 40 with regular, appropriate aerobic exercise.

What Exactly Is VO2 Max?

VO2 max measures the maximum amount of oxygen your body can take in, transport, and use during intense exercise. It depends on your heart, lungs, blood vessels, and muscles working together.

Results are reported in milliliters of oxygen per kilogram of body weight per minute. This unit lets people of different sizes compare their oxygen consumption.

Clinicians use it as one measure of cardiorespiratory fitness, also called cardiovascular fitness. A higher number usually means your heart and muscles handle physical effort more efficiently.

Why Is VO2 Max Part of the Longevity Conversation?

An American Heart Association scientific statement links low fitness with higher risk of heart disease and early death. The authors even proposed treating fitness as a clinical vital sign.

A large study of more than 122,000 adults tied low fitness to about five times the death risk of elite fitness. Benefits appeared at every level, with no clear upper limit.

These findings describe risk across large groups of people. VO2 max is a risk marker, not a prediction of exactly how long one person will live.

What Happens to VO2 Max as You Age?

Cardiorespiratory fitness generally declines with age. A long-term study of healthy adults showed that this decline speeds up with each decade, even in active people.

The same research noted that lower aerobic capacity can affect independence and quality of life later on. Still, the pace of change varies widely, depending on activity, health status, genetics, and other factors.

Why Should Women Pay Attention in Midlife?

Midlife brings changes in muscle mass, body composition, and cardiovascular risk. Maintaining fitness during this hormonal transition helps protect your ability to stay strong, active, and independent over time.

Fitness also works alongside muscle. Our article on muscle and healthy aging after 40 explains why strength matters too.

How Is VO2 Max Measured?

The most accurate measurement comes from cardiopulmonary exercise testing, often called a CPET. During this VO2 max test, you usually walk or run on a treadmill, or ride a bike. A mask measures the oxygen you breathe in and the carbon dioxide you breathe out. The effort gradually increases until you reach your limit.

Other methods only estimate VO2 max. These include treadmill or field tests, exercise machines, and fitness watches that use heart rate and pace.

Can Your Smartwatch Measure VO2 Max Accurately?

Wearables estimate VO2 max rather than measure it directly. A review of wearable accuracy studies found that these devices often overestimate VO2 max. The error averaged about 15% in resting tests and about 10% in exercise tests.

That does not make your watch useless. Garmin VO2 max accuracy, like that of other brands, varies by device and by person. The most useful information is usually your trend over weeks and months, not one reading.

What Is a Good VO2 Max for Women?

A good VO2 max depends on your age group and sex. Charts compare you with people your own age. The same score can rank differently at 40 and at 60.

Endurance athletes and elite athletes often have VO2 max scores far above average. Their numbers are not a useful benchmark for most women. A better question is whether your own fitness level supports the life you want to live.

Do You Need to Know Your Exact Number?

Not necessarily. An exact VO2 max measurement is not essential for most women. Comparing yourself with VO2 max norms or charts can also create pressure without adding much value.

Building and keeping your fitness often matters more than chasing a specific score. If you have heart symptoms or a medical condition, your provider can decide whether formal testing is appropriate.

Can VO2 Max Improve After 40?

Yes, in many cases. Regular aerobic exercise can improve cardiorespiratory fitness later in life, whatever your starting fitness level. Some women may also benefit from short intervals of harder effort when clinically appropriate.

The Physical Activity Guidelines for Americans recommend 150 to 300 minutes of moderate aerobic activity each week. They also recommend muscle-strengthening activity at least two days per week. Our guide on recovery after 40 can help you pace your training.

Fitness Is Only One Part of Longevity

VO2 max offers useful information, but it is one piece of a larger picture. Physical fitness works together with many other factors. Blood pressure, cholesterol, metabolic health, muscle strength, sleep, nutrition, smoking status, and preventive care all matter as well.

Our article on biological age tests explores why no single number can capture how you age.

Key Takeaway

You do not need an elite VO2 max to age well. The more meaningful goal is preserving cardiovascular capacity and the ability to stay active and independent over time.

At Hormona Vida, we view fitness as part of structured care. We look at patterns over time, alongside your hormonal transition and your health goals.

Curious About Your Fitness and Heart Health?

Your fitness deserves the same careful attention as the rest of your health. To review your activity, risk factors, and options in context, Speak With Our Care Team.

Frequently Asked Questions

What is a good VO2 max for women?

It depends on age and fitness level. Values decline with age, so compare yourself with women your own age, not one target number.

Is VO2 max linked to longevity?

Yes. Higher fitness is linked with lower risk of heart disease and early death. Still, it cannot predict one person’s lifespan.

How accurate is VO2 max on a smartwatch?

Smartwatches estimate VO2 max and often overestimate it. They are most helpful for tracking your own trend over time.

References

Doherty, C., Baldwin, M., Keogh, A., Caulfield, B., & Argent, R. (2024). Keeping pace with wearables: A living umbrella review of systematic reviews evaluating the accuracy of consumer wearable technologies in health measurement. Sports Medicine, 54(11), 2907–2926.

Fleg, J. L., Morrell, C. H., Bos, A. G., Brant, L. J., Talbot, L. A., Wright, J. G., & Lakatta, E. G. (2005). Accelerated longitudinal decline of aerobic capacity in healthy older adults. Circulation, 112(5), 674–682.

Mandsager, K., Harb, S., Cremer, P., Phelan, D., Nissen, S. E., & Jaber, W. (2018). Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing. JAMA Network Open, 1(6), e183605.

Office of Disease Prevention and Health Promotion. (n.d.). Top 10 things to know about the second edition of the Physical Activity Guidelines for Americans. U.S. Department of Health and Human Services.

Ross, R., Blair, S. N., Arena, R., Church, T. S., Després, J.-P., Franklin, B. A., Haskell, W. L., Kaminsky, L. A., Levine, B. D., Lavie, C. J., Myers, J., Niebauer, J., Sallis, R., Sawada, S. S., Sui, X., & Wisløff, U. (2016). Importance of assessing cardiorespiratory fitness in clinical practice: A case for fitness as a clinical vital sign. Circulation, 134(24), e653–e699.