Maximize Your Health and Fitness: A Practical Guide to Understanding and Improving VO2 Max

Runners and joggers are probably familiar with the term VO₂ max. For a casual exerciser, that term might not ring a bell to you.

But perhaps it should, especially if you’re interested in improving your aerobic workout and fitness.

VO₂ max is a measure of how effectively your heart, lungs, and cardiovascular system supply oxygenated blood to your muscles and how efficiently your muscles extract and use the oxygen from the blood (the V stands for “volume” and the O₂ represents oxygen). It’s an excellent measure of your overall health, fitness, and how intensely you should exercise.

“It’s good to know your VO₂ max because it’s a valuable piece of information to help guide exercise training that you’re regularly doing,” says Erik Van Iterson, PhD, Director of Cardiac Rehabilitation at Cleveland Clinic. “There’s not a drawback to having it directly measured. It really is the gold standard for quantifying aerobic fitness.”

What Is VO₂ Max?

The oxygen you breathe passes through your lungs, diffuses into the bloodstream and is pumped out to your working muscles. The muscles use the oxygen during aerobic metabolism to regenerate energy known as adenosine triphosphate (ATP), which is used to power muscle contractions and work during exercise. This cycle is repeated over and over. Essentially, the more effective you are at transporting and using the oxygen you inhale, the more ATP can be regenerated by your muscles to fuel your workout.

As you exercise, your body produces byproducts like carbon dioxide as a result of aerobic (oxygen-requiring) metabolism, as well as chemicals like lactic acid, or lactate, from anaerobic (non-oxygen-requiring) metabolism. If you’re less healthy, you cannot perform aerobic metabolism as efficiently or clear these byproducts as effectively. Once these byproducts build up to a certain level, your muscles become fatigued to the point where you can no longer exercise, Dr. Van Iterson explains.

VO₂ max is an accurate, objective measurement of your cardiometabolic functionality and your exercise endurance capability. It provides an individualized blueprint for how much aerobic exercise (cardio) you can perform and how intensely you should do it based on your actual physiological performance. As a result, parameters like target heart rate zones can be identified, rather than relying on generalized calculations derived from populations of people (such as subtracting your age from 220 and exercising at a percentage of that result), Dr. Van Iterson says.

“You’re better able to identify the point at which your lactate, or anaerobic, threshold sets in, so that you can identify the equivalent heart rate at that anaerobic threshold point and more precisely and accurately determine your target heart rate level,” he says. “By undergoing testing to know what your VO₂ max is, you acquire multiple reference data points for determining what would be your optimal target heart rate during aerobic exercise.”

How VO2 Max Is Measured

VO₂ max is measured in milliliters of oxygen consumed per minute per kilogram of body weight (mL/kg/min). To get a true assessment, have your VO₂ max directly measured in a clinical exercise testing laboratory. For the test, you’ll ride a stationary bicycle or walk, jog or run on a treadmill for about eight to 12 minutes, during which time the workload continuously ramps up until you reach your point of voluntary fatigue. During the test, you’ll wear a heart rate monitor and a mask over your nose and mouth that records your oxygen uptake and carbon dioxide output.

Instead of directly measuring true VO₂ max, which is a more time-intensive and technically involved assessment characterized by achieving a plateau in your oxygen uptake, many experts commonly quantify VO₂ peak as a surrogate for VO₂ max. VO₂ peak represents your highest oxygen uptake recorded near or at the very end of the test. This value is then combined with measures such as your rating of perceived exertion (your subjective assessment of how hard you’re working) and the respiratory exchange ratio (calculated by dividing your carbon dioxide output by your VO₂), Dr. Van Iterson says.

“The field is accepting this concept of VO₂ peak as being interchangeable with VO₂ max for most adults,” he adds. “Typically, because interpreting VO₂ peak by itself is near impossible in most situations, you use a combination of measurements to determine if you’ve reached your true VO2 peak, in place of having to do the traditional VO₂ max and watching for the plateauing effect.”

Several online calculators, as well as smartwatches, fitness trackers and other wearable technology, advertise that they can estimate your VO₂ max. However, “I don’t recommend using smartwatch technology or online calculators to try to estimate it at home,” Dr. Van Iterson advises. “There’s a reason why there’s a rigid, scientifically studied protocol to get this measurement done. Building an equation or algorithm online or in a smart device does not encompass all the scientific principles that need to be taken into account to have the VO₂ max measurement mean what it should.”

Average Expected VO₂ Peaks

This table shows what an average expected VO₂ peak (performed on a stationary cycle) would be for a 6-foot-tall man based on age and body weight.

<table>
<tbody>
<tr>
<td rowspan=”2″ width=”41″>
<p><strong>Age</strong></p>
<p><strong>65</strong></p>
</td>
<td width=”144″>
<p>Weight</p>
</td>
<td width=”66″>
<p>175 lbs</p>
</td>
<td width=”73″>
<p>185 lbs</p>
</td>
<td width=”73″>
<p>195 lbs</p>
</td>
</tr>
<tr>
<td width=”144″>
<p>VO2 peak (mL/kg/min)</p>
</td>
<td width=”66″>
<p>27.4</p>
</td>
<td width=”73″>
<p>26.6</p>
</td>
<td width=”73″>
<p>25.6</p>
</td>
</tr>
<tr>
<td rowspan=”2″ width=”41″>
<p><strong>Age</strong></p>
<p><strong>70</strong></p>
</td>
<td width=”144″>
<p>Weight</p>
</td>
<td width=”66″>
<p>175 lbs</p>
</td>
<td width=”73″>
<p>185 lbs</p>
</td>
<td width=”73″>
<p>195 lbs</p>
</td>
</tr>
<tr>
<td width=”144″>
<p>VO2 peak (mL/kg/min)</p>
</td>
<td width=”66″>
<p>25.5</p>
</td>
<td width=”73″>
<p>24.9</p>
</td>
<td width=”73″>
<p>23.9</p>
</td>
</tr>
<tr>
<td rowspan=”2″ width=”41″>
<p><strong>Age 75</strong></p>
</td>
<td width=”144″>
<p>Weight</p>
</td>
<td width=”66″>
<p>175 lbs</p>
</td>
<td width=”73″>
<p>185 lbs</p>
</td>
<td width=”73″>
<p>195 lbs</p>
</td>
</tr>
<tr>
<td width=”144″>
<p>VO2 peak (mL/kg/min)</p>
</td>
<td width=”66″>
<p>23.6</p>
</td>
<td width=”73″>
<p>23.1</p>
</td>
<td width=”73″>
<p>22.2</p>
</td>
</tr>
</tbody>
</table>
<p>mL/kg/min = milliliter per kilogram of body weight per minute | lbs = pounds</p>
<p><em>Source: Erik Van Iterson, PhD, Cleveland Clinic</em></p>

Factors That Affect VO₂ Max

A number of factors can affect your VO₂ max, such as your age (VO₂ max naturally declines with age), genetics, gender (men typically have higher VO₂ max levels than women), body composition, chronic and acute health conditions, and your current physical activity level.

Consequently, “There is no universal, applicable normal VO₂ peak value that you should be going by at this point, so you should probably ignore that if you’re reading it somewhere,” Dr. Van Iterson advises. “But that’s a reason to get your VO₂ max directly tested if you’re interested, because you’d get your VO₂ number and have that reported as a percentage of the predicted peak for a person your age, body weight, sex, and height. So, you get both an absolute measurement as well as a relative to your peers.”

Why VO2 Max Matters for Your Health

Aerobic exercise is vital for maintaining the health of your heart, lungs, and blood vessels, and VO₂ max is an excellent indicator of your cardiovascular, respiratory, and metabolic health. Ample scientific data have linked a higher VO₂ max with lower risks of several chronic diseases, including cardiovascular disease, stroke, cancer, and diabetes. Other research suggests that better cardiorespiratory fitness, based on VO₂ max, is associated with higher energy and stamina levels and improved overall quality of life and longevity.

VO₂ max is also a valuable tool to help you exercise safely and efficiently so that you can continue to boost your cardiorespiratory fitness and, potentially, your longevity.

“It’s quite easy to accidentally overdo it if you’re just getting started with exercise and you’re not familiar with how your body should feel when you’re exercising,” Dr. Van Iterson says. “If you start off too fast with the exercise, your body is going to give you symptoms of overdoing it—such as fast breathing, a racing heart, or a sudden onset of heat, fatigue, pallor, or dizziness—before you realize you shouldn’t have done as much as you did.

“It becomes more difficult when you’re in late adulthood to know what a good training heart rate is,” he continues. “So having actual test measurements could potentially be even more valuable for older adults from the perspective of knowing what the ideal target training zone is.”

How to Improve Your VO₂ Max

Building your VO₂ max requires a simple strategy: Do cardio. Whether you walk briskly around your neighborhood, jog around a track, or stay indoors and use a treadmill or stationary bike, you need aerobic exercise to increase your endurance and improve your cardiorespiratory fitness. To be most effective, your aerobic exercise should be intentional, meaning dedicated time spent exercising for the sake of exercise, as opposed to trying to get it in while doing something else. Doing things like yardwork is not going to be effective cardio and won’t improve the VO₂ max for most adults.

Work within your submaximal target heart rate zone, and build up gradually, based on the advice of your healthcare provider. Pushing for the highest heart rate intensity every time you exercise is not necessary or effective for most adults, Dr. Van Iterson says. Once you’ve trained consistently for a while and your conditioning has improved, ask how to strategically incorporate some higher-intensity cardio into your routine or increase the duration of your exercise sessions to help continue your VO₂ max improvements.

Using VO₂ Max to Guide Your Fitness

Set achievable short-term goals that are geared toward setting you up for long-term exercise success, and then consider having your VO₂ max rechecked in a year to see how you’ve progressed and what adjustments you might need to make, Dr. Van Iterson recommends.

“Always looking for VO₂ peak or VO₂ max to increase year after year for the rest of your life isn’t necessarily a fair expectation, but rather aim to lessen the decline on a yearly basis,” he advises. “For older adults, it should be viewed as a positive to lessen the decrease in VO₂ peak and VO₂ max year after year.

“There’s no need to make the exercise fancy or involved to change the VO₂ max, and it also doesn’t require an exhaustive amount of time—just start off at 15–20 minutes per session three days per week and gradually increase minutes and days per week,” he adds. “Importantly, be consistent. You really have to do this year-round. The goal is not intensity; it’s consistency. And if you try to do it more intensely than you should, you’re going to compromise the consistency.”