Most cyclists, at some point, want to see how fast and hard they can go, even for just a few minutes. Riding at that nearly all-out intensity, when you’re breathing heavy and can barely talk, is likely your VO₂ max (or close to it). Scientifically speaking, VO2 max is the maximum amount of oxygen your body can take in and use and it’s a marker of your cardiovascular fitness level.
For a variety of reasons, VO₂ max naturally decreases as you get older. Fortunately, athletes are more likely to minimize this decline through consistent and purposeful training.
Read on for more information about VO₂ max by age, including how it’s determined, and how to make sure your rides help maintain this important metric as you get older.
Why does VO2 max matter?
Of all the available health and fitness metrics, VO₂ max is one of the most important. “VO₂ max is the amount of oxygen that you can breathe in, transport to the muscle, and utilize during maximal exertion and aerobic exercise,” Todd Buckingham, Ph.D., exercise physiologist at PTSportsPRO in Grand Rapids, Michigan tells Bicycling.
He explains that, besides being an indicator of overall fitness, it’s also a “gold standard” measurement of an athlete’s ability to perform well in an endurance event; essentially, the higher your VO₂ max, the greater your potential. “Once your VO₂ max gets to a certain level, other things like lactate threshold and exercise efficiency come into play. But VO₂ max is the first step in determining performance,” Buckingham says.
VO₂ max, which is measured as milliliters of oxygen per kilogram of bodyweight per minute (ml/kg/min), is most accurately assessed in a laboratory environment. During the test, you wear a specialized mask that measures inhaled oxygen and exhaled carbon dioxide while you pedal an exercise bike, run on a treadmill, or swim in an endless pool. Over the course of 12 to 15 minutes, you increase the exercise intensity so that, by the end of the test, you pushed your aerobic limits.
Getting access to a lab can obviously be time consuming and expensive, so you can also turn to your fitness tracker to help establish a baseline and keep tabs on how your fitness is improving. The caveat: You have to take those numbers with a grain of salt. Research shows that many wearables over- or underestimate VO₂ max by up to 10 percent.
Why does VO2 max decline as you age?
Like many markers of health and fitness, VO₂ max naturally declines as you age. “VO₂ max tends to peak for men in their mid-to-late 20s. For women, it’s a little later, like early 30s. But after it reaches the peak, it tends to decrease,” Buckingham says.
Some research indicates that the average person can expect around a 10 percent decline in VO₂ max after age of 30. (This is particularly true for males, the study suggests.) However, the drop may be even more drastic among athletes. According to a recent study published in a 2024 issue of Experimental Gerontology, aging had a greater affect on VO₂ max in female runners than in sedentary women. The scientists hypothesized that the younger athletes started with a higher VO₂ max than their sedentary peers and, therefore, had further to fall. Despite this more drastic decline, active women still had better VO2 max than their non-active peers.
Generally speaking, though, age-related reductions in VO₂ max are likely due to a combination of factors, including a reduction in cardiac output. Cardiac ouput is the product of the number of times your heart beats per minute (heart rate) and the volume of blood ejected with each contraction of the heart (stroke volume). As you age, both the amount of blood your heart pumps out to the body and your maximal heart rate go down. Older individuals may also experience a reduction in blood circulation.
Age-related muscle loss, a.k.a. sarcopenia, may also be to blame for a decline in VO₂ max. “We tend to lose muscle mass and increase body fat percentage [as we get older],” Buckingham says. “Because fat does not have mitochondria and capillaries to turn oxygen into energy, we have metabolically inactive tissue.” (Mitochondria are the parts of cells that use oxygen to manufacture adenosine triphosphate (ATP), our primary energy currency.)
In other words, with lower muscle mass comes the loss of capillaries and mitochondria, making your body less energy efficient.
VO2 Max by Age Chart
Wondering what’s a typical rate of decline for VO₂ max? The chart below contains research-based averages of VO₂ max by age and fitness level, for men and women. Remember that each individual’s VO₂ max score depends on multiple biological and lifestyle factors; these are just a range of average scores.
How do you fight VO2 max declines as you age?
While everyone gets older, not everyone loses VO₂ max at the same rate. “There’s the saying, ‘We don’t stop exercising because we get old. We get old because we stop exercising,’” Buckingham says. “Just by being active, you can prolong that level of VO₂ max. Obviously, at some point, the atrophy process is going to occur. It just happens as we get older. But you can maintain it for a lot longer when you’re active than if you were just sedentary.”
If you’re already following a training program that includes a mix of easy, steady-state rides, more intense workouts, and strength training, stick with that diversified approach.
Lower intensity, or “zone 2” workouts are especially important. “When you are exercising at lower intensities, you produce more mitochondria and capillaries. Mitochondria is where the oxygen is transformed into energy, and the capillaries are the vessels that actually take the oxygen from the blood to get it into the muscle to then get it into the mitochondria to produce energy,” Buckingham explains.
Higher-intensity exercise is also essential, as it increases the size of each mitochondrion (“so we can get more oxygen into it,” Buckingham says). High-intensity exercise, Buckingham explains, necessitates a longer recovery period.
To maximize the benefits of your workouts while avoiding burnout, Buckingham recommends the 80/20 training methodology: 80 percent of your workouts are low-intensity and 20 percent are performed at higher intensities.
Strength training is also critical, as it can combat sarcopenia and maintain muscle mass. As previously noted, muscle mass is critical to VO₂ max, as it contains mitochondria and capillaries.
A pretty valid case for making these workouts a part of your regular routine: Research suggests that higher VO₂ max levels may be associated with a longer lifespan. One study published by the Journal of the American College of Cardiology followed a cohort of more than 5,000 men for 46 years. Researchers found that higher rates of cardiorespiratory fitness, as determined by VO₂ max, were associated with longer lives.
