Running faster with less effort probably feels like the dream. When an eight-minute mile feels like a nine-minute mile, it’s like you could set new PRs left and right.
If that is your goal, there is one measurement you should pay particular attention to—your VO2 max. Scientists study this marker of fitness in numerous ways, and you may have even seen an estimate of it on your watch.
To help you understand this metric and how to increase VO2 max, we have your complete guide.
What is VO2 max?
It shouldn’t come as a surprise that as you start running, your body undertakes a series of physiological changes designed to support your increased effort. Two of the most obvious changes are that you start breathing harder as your heart starts pumping faster. You need this increase in breath rate and heart rate (your heart pumps the oxygenated blood to your working muscles) because your body requires oxygen to create energy for sustained cardiovascular exercise.
The more oxygen you can efficiently consume and use, the easier exercise will feel at a given intensity level. That, in very simple terms, is the benefit of training to improve your VO2 max.
“VO2 max is the measurement of the maximum oxygen delivery and utilization for cardiovascular exercises,” says Jamey Plunk, Ph.D., professor of exercise physiology at the University of Mary Hardin-Baylor. “It’s trainable and de-trainable, and to some extent, it’s governed by genetics—any individual will only be able to reach their genetic maximum potential VO2 max through training.” In other words, while just about everyone can increase their VO2 max, not everyone has the genetic potential to be Eluid Kipchoge.
Think of it like the efficiency of your own internal engine: “A high VO2 max is like a car with a bigger engine. A car with a smaller engine has to work harder to go as fast as the big engine,” says Matthew Luke Meyer, certified run coach based in Boulder, Colorado.
Plunk also points out that very few people ever reach their maximum genetic potential for VO2 max due either to a lack of motivation or a lack of training knowledge. This is important to understand, because a high level of motivation to get better at running will only take you so far. You have to know how to effectively train for the sport if you want to see the greatest improvements over time.
What are the benefits of improving your VO2 max?
The most obvious benefit of increasing your VO2 max is the potential improvements you’ll see in your running performance. While VO2 max is a great marker to know—understanding and tracking your cardio fitness can help you set appropriate goals and evaluate your training—no plan or coach would ever suggest heading out on a run at, say, 80 percent of your VO2 max.
Instead, your VO2 max is used to identify more useful parameters: your heart rate zones and anaerobic threshold, says Silvano Zanuso, Ph.D., director of the medical and scientific department at Technogym. In this way, the test provides you with the most accurate zones and thresholds to plan your training around, he says.
If you’re unfamiliar with the anaerobic threshold, it’s essentially the breakpoint where your intensity level is too high to keep up with the energy demands required for exercise that are provided through oxygen consumption alone (aerobic means “with oxygen”).
Even as you breathe harder and harder, you start feeling your working muscles burn, indicating that you’re not getting enough oxygen needed to sustain the level of effort you’re exerting. Your body has started to use anaerobic systems (anaerobic means “without oxygen”) to help you continue to move. Eventually, you have to slow down or stop, returning to an aerobic level of intensity.
“A higher VO2 max is also indicative of a higher anaerobic threshold, which, by definition, means a higher level of lactic acid tolerance. Functionally, this means that a level of exertion that used to be anaerobic and short-term for you—producing lactic acid—can now become aerobic with longer duration potential,” Plunk explains.
In other words, if sustaining a pace of 8:30 per mile for more than five miles used to make your quads burn, the better your VO2 max, the greater chance that you’ll be able to sustain that pace for more than five miles, or improve your pace for the same length of time.
Even if you don’t have any major performance improvement goals, an improved VO2 max can also be a boon for general health. “An increase in VO2 max is essentially an improvement in cardiovascular capacity for any kind of work. This type of improvement reduces the daily workload on the heart,” Plunk says.
Given that cardiovascular disease is still the leading cause of death in the United States, most Americans’ hearts could benefit from being a little less taxed during day-to-day activities. Plus, research also links a higher VO2 max with a lower risk of certain cancers.
How do you increase VO2 max?
If you’re even modestly familiar with the concept of VO2 max and its improvement, you probably won’t be surprised to hear that high-intensity interval training (HIIT) is considered one of the best ways to increase your measurements.
Study after study confirms that HIIT training can effectively improve your VO2 max. This is because HIIT causes you to toy with or temporarily surpass your anaerobic threshold before returning to a lower, aerobic intensity. This type of overload causes your heart and lungs to adapt to the demands being asked of them.
“The process of raising a VO2 max is similar to increasing strength gains in a muscle,” Plunk says. “A muscle will only gain up to what is demanded of it. It will not get stronger than what is customarily required. The same applies to VO2 max. If a higher demand is placed on the cardiovascular system, then the capacity to tolerate those demands will increase up to a genetic limit.”
This concept explains why constantly running the exact same distance at the exact same pace for the exact same times won’t help increase your VO2 max beyond any initial gains you may have experienced.
On the road or track, you’ll have to push your limits with tempo runs and intervals at threshold, but you don’t want all of your runs to be hard. In fact, about 70 to 80 percent of your run training should be easy runs, which is why it makes sense to add HIIT to your gym or home routine. “You want to do something that will force variation in your heart rate, so spike it straight up and drop it back down,” says Greg Laraia, a certified athletic trainer and head run coach at Streets 101.
This could mean total-body exercises such as sled pushes, ball tosses, plyometric jumping, ladder drills—“basically anything that’s going to exert more energy than a simple bench press,” he says.
As far as reps and sets go, Laraia suggests starting with the basic three sets of 12 to 15 reps for bodyweight moves to keep your heart rate up and maintain proper form. Some research suggests you go for supersets, minimizing rest between moves, but taking 30 seconds between sets.
The key with at-home HIIT workouts—or any workout in which your goal is improving VO2 max—is that you should be working at an intensity right below your anaerobic threshold (the point at which you start feeling lactic acid build in your working muscles), and you should exercise at this level of exertion for at least 15 minutes.
If HIIT workouts just aren’t your thing though, there’s good news: Plunk says that any workout that’s done regularly and places a higher, continuous demand on the cardiovascular system can increase your VO2 max.
Beyond intervals, Plunk suggests continuous hills, tempo running, cycling, swimming, or any cross-training activity that places similar demands on your system.
Whichever method you choose, another key is to stick with it. Increasing your VO2 max won’t happen overnight, but the more fit you are, the more time it takes to see the improvement. Plunk says if you’re out of shape to moderately fit, you may see improvement in as little as four to six weeks, and if you are very fit, it could take as long as four to six months.
How can you estimate your VO2 max?
You can have your maximum capacity tested at performance labs, physical therapy facilities, and medical centers, but because it’s so uncomfortable (think: a dizzying all-out effort on a treadmill that leaves many close to puking), costly ($150 to $250), and not advised for all (all-out efforts are considered dangerous for some populations), many opt for a sub-max test or a formula like the one here instead.
Calculate yours with your age, resting heart rate, and maximum heart rate:
VO2 max = 15.3 x (MHR/RHR)
You could also try a watches that includes a VO2 max estimation feature. The more you wear the watch, the more accurate your number will be. Generally, wearables tend to underestimate because we very rarely hit the top end of our capacity while working out. That said, they all use your heart rate during certain workouts while also taking into account other factors, such as distance or altitude, to provide a fuller picture of your VO2 max.
