Why VO2 Max Matters

VO2 max indicates how well your lungs consume oxygen, how effectively your heart sends blood to your muscles, and how efficiently your muscles extract oxygen from the blood. Think of it as a sophisticated way of understanding how fit you are.

Not only does VO2 max tell you about your cardiorespiratory health, but research shows VO2 max is a key indicator of longevity. The American Heart Association has recommended incorporating VO2 max into routine clinical evaluations because of its predictive value, and a 2018 review in Frontiers of Bioscience-Landmark found VO2 max is associated with reductions in all-cause mortality, calling it the strongest predictor of life expectancy.

VO2 max is expressed as milliliters of oxygen per minute per kilogram of body weight, and a higher number generally means you’re in better cardiorespiratory shape. Doctors and performance specialists typically compare an individual’s VO2 max against established benchmarks for people of similar sex and age to help understand the person’s current state of fitness.

How to measure VO2 max

While research has shown that genetics and age play a major role—VO2 max typically decreases 2% per year after age 30!—you can improve your VO2 max by adjusting the duration, type, and intensity of your training.

Experts say that while wearables such as Oura Rings or Apple Watches can estimate your VO2 max, the best way to get an accurate assessment is to undergo a test in an exercise lab or performance gym. This usually involves working out on a treadmill or bike while wearing a mask that measures how much oxygen you’re inhaling and how much carbon dioxide you’re exhaling. Tests cost around $150-300.

A VO2 max test places significant demand on the cardiovascular system, so many experts recommend a cardiac evaluation before undergoing VO2 max testing, especially for older adults, those with risk factors such as hypertension, diabetes, smoking, and dyslipidemia, or anyone with symptoms of cardiovascular disease.

Other fitness biometrics that matter

VO2 max isn’t the only metric to track. Other measurements can also tell us about metabolic fitness, and some of these may be a better guide when setting exercise targets, especially for training intensity, performance improvement, and aerobic endurance.

1. Lactate threshold is the point during a workout when lactate builds up in the blood faster than it can be removed. This indicates the intensity of exercise you can sustain for longer periods without becoming excessively fatigued. Lactate threshold can be modified with proper training. As this threshold increases, you’ll notice you can keep exercising harder and longer.

How to measure it: During a VO2 max test at a performance gym or sports clinic, you’ll have your finger pricked at each stage as exercise ramps up and clinicians will measure the lactate levels.

2. Metabolic efficiency point (MEP), also called the crossover point, marks when the calories you’re burning come from carbohydrates and fat in equal amounts. People typically burn fat during lower-intensity workloads and transition to carbs as a workout increases in intensity, so finding your MEP can help you plan workouts to meet your goals. For instance, if you are trying to reduce body fat, you will want to stay under your MEP for longer.

How to measure it: This is also typically measured during a VO2 max test. Clinicians or fitness specialists will track your calorie usage throughout the workout to identify your MEP, and you can use whatever your heart rate is at that crossover point to inform your training.

How to improve these biometrics

National guidelines recommend 150 minutes of cardiovascular exercise per week. About 80% of that should be done at a moderate-intensity level of exertion (zone 2 or 3 on the training zone scale), according to Peter Modera, a physical therapist at the Atria Health Institute. In these zones, you can still carry on a conversation, but anyone talking to you would know you’re working out. This will build a foundation for your fitness and lead to improvements in cardiorespiratory and metabolic health.

“Zones 2 and 3 build your aerobic base and improve your body’s ability to use fat as an energy source, but if you want to improve your VO2 max, you also want to raise your ceiling,” Modera says. This can be done by spending 20% of your workout time on high-intensity interval training.

Note that for overall health, strength training is also critical. Experts recommend at least 2 days of moderate to high-intensity muscle-strengthening activity per week.

Ultimately, keeping track of your biometrics puts you in a much better position to understand your metabolic health and exercise over time. However, it’s important to remember that these numbers are tools. Rather than obsessing over specific values, use them as a guide to support your overall well-being and fitness journey.

This article is part of Atria’s Future of Health newsletter. Subscribe here.