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The Running Metric That Can Change Your Game

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Last updated: June 1, 2021
Why Runners Should Care About VO2 Max

A lot of important numbers can help you determine how your body is handling any given run: pace, goal time, heart rate and your effort on a scale from 1 to 10, to name a few. Your VO2 max, a benchmark for aerobic fitness, is one of those key stats—but it's often overlooked. 

To understand how improving this number can make you a better runner and healthier person in general, we've pulled in experts to break it down.

The longer you can run without getting tired, the higher your VO2 max probably is.

Ian Klein
Exercise Physiologist

What Is VO2 Max?

The "V" stands for volume, "O2" for oxygen and "max" for maximum. Together, they represent a measurement of the highest volume of oxygen your body can use during exercise. That number is important because it can indicate how fit you are and help you structure your workouts so you can work towards a healthier you.

Calculating VO2 max is complicated stuff. For starters, the measurement is typically expressed as millilitres of oxygen consumed per kilogram of body weight per minute (ml/kg/min). And to precisely capture that, it's traditionally tested in a sports-science lab while an athlete runs their heart out on a treadmill, says Aaron Coutts, PhD, a distinguished professor in sport and exercise science at the University of Technology Sydney.

Know that there's no accurate way to measure VO2 max at home (while some activity trackers claim to, the best ones still only estimate it). But for those of us who aren't elite competitors, we don't need the lab. We don't even need an activity tracker. It's actually pretty easy to tell when your VO2 max is increasing, and that's what you need to know to use it to your advantage. "It's based upon fitness", says Ian Klein, an exercise physiologist specialising in cross-training and injury prevention at Ohio University. "The longer you can run without getting tired, the higher your VO2 max probably is".

Why Runners Should Care About VO2 Max

How VO2 Max Connects to Your Speed 

Why should runners give a damn? A higher VO2 max means your body can deliver more oxygen to your muscles as you run, which can equip you to go faster even as your workouts get harder, explains Klein. Usually, if you have a high VO2 max you also have a high lactate threshold. That means you can work at a higher intensity for longer before your body begins to build up lactic acid, fatigue sets in and you're forced to pull back.

Most runners are familiar with that "Ugh, I can't" feeling, which is typically experienced when crossing what's called the anaerobic threshold. Here's what's going on to cue it: Your muscles start to build up hydrogen ions and lactate faster than your body can clear them, says Klein. All that hydrogen gets converted into carbon dioxide, he says, and the more carbon dioxide you have, the harder it is for oxygen to be transported. And with no more oxygen, guess what? No more sprinting.

The better your VO2 max, the more efficiently your body can remove that carbon dioxide, and the more oxygen your red blood cells can hold and shoot to your muscles to keep pumping, says Klein. Specifically training to boost your VO2 max (more on how to do that below) also helps develop more capillaries in the muscles, says Klein, which—again—means you can get more oxygen to the muscles. "Once the oxygen is there, it's easy to turn into energy", he says, helping you run stronger and faster.

Why a Better VO2 Max Means Better Health

A higher VO2 max is a win-win outside of running too, because your lungs can more efficiently take in and send oxygen to your muscles, including your heart. This means your heart is able to pump more blood with each heartbeat, which lowers your resting heart rate. In short, your entire cardiovascular system will be under less stress.

To grasp the long-term health effects of this, look at the other end of the spectrum. Low levels of cardiorespiratory fitness, or a lower VO2 max, are associated with a high risk of cardiovascular disease and various cancers, according to the American Heart Association. In fact, the AHA says cardiorespiratory fitness is a stronger predictor of mortality risk than smoking (!) and high blood pressure.

That could explain why research shows that improving your VO2 max may reduce your risk of serious health conditions. As if beating your 5K PR wasn't enough.

How to Up Your VO2 Max

The bad news: Your potential for your highest VO2 max is influenced by genetics (another reason why most of us will never run like Eliud Kipchoge). The good news: You're likely to be a long way from operating at your uppermost threshold.

To do that, you want to play to the fitness spectrum. Be comfortable running long, slow distances and doing faster, more challenging workouts. Once you've established a good base of fitness (you'll know you have when those slower and faster workouts feel easier), you can do more HIIT. As you may know, these sessions alternate hard or all-out efforts with recovery bouts. And doing them is one of the most effective ways to increase your VO2 max and lactate threshold, according to research, including a study in the journal Medicine & Science in Sports & Exercise, which found HIIT to be better than endurance training for boosting VO2 max.

How, exactly? Well, holding higher intensities for short intervals pushes your anaerobic system to its lactate threshold, Klein explains. Over time, this makes the system more efficient at performing at those intensities for longer periods. He says the intensity you're shooting for falls somewhere between an 800-metre sprint and an all-out 2-mile pace. This kind of gnarly effort, Klein says, "provides the metabolic and physiological stress your body needs to adapt, grow stronger and increase your VO2 max". Try sprinting for 30 seconds, recovering for 30 seconds, and repeating for 5 to 10 minutes. Or score a similar VO2 improvement by training on hills, taking them on as fast as you can. For specific HIIT and hill workouts, check out the Nike Run Club App.

Now that you've got the intel, use it as fuel to take it to the max in your next interval workout.

Words: Ashley Mateo
Illustration: Kezia Gabriella

Why Runners Should Care About VO2 Max

Take It Further

For more expert-backed guidance on movement, as well as mindset, nutrition, recovery and sleep, check out the Nike Training Club App.

Take It Further

For more expert-backed guidance on recovery, as well as mindset, movement, nutrition and sleep, check out the Nike Training Club App.

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