In the realm of athletic performance and longevity, one metric stands out as a key indicator of cardiovascular fitness and endurance: VO2 max. This metric, a measure of maximal oxygen uptake, serves as a crucial benchmark for athletes and non-athletes alike, providing insights into overall health (and thus longevity), fitness levels, and potential for peak performance. In this blog post, we'll delve into what VO2 max testing entails, its benefits for both performance and longevity, and the various methods used to assess it.
“Peak aerobic cardiorespiratory fitness, measured in terms of VO2 max, is perhaps the single most powerful marker for longevity.”
Peter Attia
What is VO2 Max?
VO2 max refers to the maximum amount of oxygen your body can utilize during intense exercise. It is measured in milliliters of oxygen per kilogram of body weight per minute (mL/kg/min) and is considered one of the most accurate ways to gauge an individual's cardiorespiratory fitness and endurance capacity.
During exercise, your muscles require oxygen to produce energy aerobically. VO2 max represents the upper limit of your body's ability to deliver oxygen to the muscles and utilize it for energy production. Essentially, the higher your VO2 max, the more efficiently your body can transport and utilize oxygen, leading to improved endurance and performance. What are the benefits of having a high VO2 max?
Benefits for Performance:
Enhanced Endurance: Athletes with higher VO2 max values can sustain intense exercise for longer durations without fatigue. This translates to improved performance in endurance sports like long-distance running, cycling, and swimming.
Improved Recovery: A higher VO2 max often correlates with better recovery rates during and after exercise. This means athletes can push themselves harder in training sessions while reducing the risk of overtraining and injury.
Better Anaerobic Threshold: VO2 max testing can also determine an individual's anaerobic threshold—the point at which the body switches from aerobic to anaerobic metabolism. This information is invaluable for pacing strategies and optimizing training intensity.
Benefits for Longevity:
It may come as no surprise that being fit is associated with longer life. But you may be surprised to learn just how good for you it is to be fit. For perspective, consider a study like the one in the 2018 Journal of the American Medical Association. Smoking, widely acknowledged to be a detriment to longevity, was associated with a 40% greater risk of mortality from any cause. Compared to an elite level of fitness (top 2.3 percent), someone in the bottom quartile of fitness (bottom 25 percent) had 5 times greater risk of dying.
Not everyone can achieve elite fitness and be in the top 2%. But almost anyone can improve from ‘low’ to ‘below average.’ This level of improvement, from the bottom 25 percent to the 26-50 percentile, cuts the associated risk of mortality almost in half. Although there are genetic inputs to VO2 max, this capacity is highly trainable.
VO2 max declines 10% per decade as we age (Kim et al. 2016). The largest determinants of this decline appear to be the decrease in the maximum achievable heart rate and loss of lean muscle. You can’t stop your age-related decline in maximum heart rate, but you can fight against loss of lean muscle. Decline in VO2 max, however, can become non-linear in certain situations: (1) cessation of training, (2) age over 70 and (3) in the 20s and 30s for sedentary individuals (yikes!). (Hawkins et al. 2003)
This decline is important to keep in mind not just from a lifespan but also from a healthspan standpoint. To a great extent, your VO2 max will determine your quality of life. And if you haven’t banked enough fitness in youth and middle age, you’re going to run out of gas in old age. It’s the exercise version of financially saving for retirement. Once your VO2 falls below a certain threshold (18 mL/kg/min for men and 15 mL/kg/min for women), you may lose your ability to live independently (Shephard 2009). Take for example someone in his 20s who is completely sedentary and has a VO2 max of 25 mL/kg/min. At a 10% decrease per year, he may lose the ability to live independently in his 60s, purely on the basis of cardiorespiratory fitness (to say nothing of the effect of disability or disease).
What numbers represent different fitness levels for age and gender? See the representative charts below from firstbeat.com
VO2 Max for women by age group
VO2 max for men by age group
Any improvement in VO2 max will benefit you, but if you’re up for the challenge proposed by Dr. Attia, aim for elite fitness for your gender, but two decades younger.
Methods of Assessment:
Laboratory Testing: The gold standard for measuring VO2 max involves a graded exercise test performed on a treadmill or stationary bike under controlled laboratory conditions. During the test, oxygen consumption is measured while the intensity of exercise gradually increases until the participant reaches their maximum effort (failure).
Field Tests: Various field tests, such as the Cooper test, the 1.5-mile run, or the Rockport 1 mile walk test, provide estimates of VO2 max based on performance in specific exercises. While not as accurate as laboratory testing, they are nonetheless highly accurate and much more accessible. These assessments offer a practical and cost-effective way to gauge cardiovascular fitness in real-world settings.
Wearable Technology: Advances in wearable fitness technology have made it possible to estimate VO2 max using devices like heart rate monitors and GPS watches. These tools analyze heart rate variability, exercise intensity, and other metrics to provide users with personalized fitness assessments. These correlate with a measured VO2 max, but I would consider these the least reliable. Since they are based on proprietary algorithms, they are also relatively opaque.
Methods of Training:
VO2 max responds to interval training, but not the high intensity interval training that you might think of popularly associated with intervals. VO2 max intervals range from 3 to 8 minutes, with an equal amount of time for recovery. There are many ways to put together an interval program, but four to six intervals (with a warm up and cool down) can easily form a VO2 max training day. Once a week is adequate as a minimum for this specific type of training.
VO2 max testing serves as a valuable tool for assessing cardiovascular fitness, guiding training programs, and promoting overall health and longevity. Whether you're an elite athlete striving for peak performance or an individual looking to improve your longevity and healthspan, understanding and monitoring your VO2 max can unlock new levels of achievement and vitality in your fitness journey.