Base Knowledge: VO2 Max

A brief explainer of everyone's favorite geeky fitness metric and why even non-athletes can use it.

Today’s newsletter centers around a question from our Clubhouse Community—a perk for all you terrific paid subscribers.

NPB Athlete Shannon Hulzebos writes, “Will increasing your VO2 max also increase one's endurance and does it impact you at a cellular level or is it only related to your lungs?”

Thanks for the great question, Shannon! VO2 max doesn’t technically fall under the NPB nutritional purview, but I’ve known Shannon a long time and she’s a good egg, so let’s take a quick look.

VO2 max is short for "volume oxygen maximum." Personally, I would have gone with the more grammatically logical “maximum oxygen volume,” or Max O2V, but I was not consulted, given the term was coined in 1923.

What is VO2 max?

Simply put, it's a measurement of the maximum amount of oxygen your body can process during exercise. A higher number means your cardiorespiratory system can work harder. So, to directly answer Shannon’s question, I’d say the organs it’s most related to are the lungs, heart, and muscles.

When you breath, you inhale oxygen (among other things). Your lungs pass that oxygen to your blood. Your heart pumps that blood to all the cells in your body—including the ones in your muscles—where the oxygen takes part in a process called aerobic cellular respiration. It reacts with glucose (blood sugar) and creates something called adenosine triphosphate, or ATP. Your cells use ATP as fuel.

When you do aerobic exercise, your muscle cells need a lot of this ATP, so the more oxygen they get the better. Again, VO2 max measures how much oxygen your muscles can uptake.

VO2 max is measured in units called metabolic equivalents, or METs. A MET is 3.5 milliliters of oxygen divided by your weight in kilograms (kg) times one minute. No need to take notes on this equation. There will not be a test.

To officially determine your VO2 max, you need to use a stationary bike or treadmill in a lab while hooked up to all kinds of equipment. You can get it done at a sports medicine facility for a couple hundred bucks.

There are various calculations you can use to estimate VO2 max. Also, many smartwatches estimate your VO2 max. My Garmin Forerunner 945 lets me know my estimated VO2 max after every workout.

These are great tools, but keep in mind that they are estimates that probably don’t hit the mark, so don’t hang your hopes and dreams on the number. The best way to use them is to chart progress. If your watch says your VO2 max is 45, that may not be true. However, if you work your tail off and your watch tells you that your VO2 max has gone up three points to 48, it’s reasonable to assume you’ve made a respectable cardiorespiratory fitness gain!

What good is VO2 max to me?

If you’re an athlete, it’s a fitness metric like any other. After a while, you get to know your VO2 max range, so you can use it to know where you stand in your training. For the non-athlete, it’s a good indicator of general cardio health. VO2 max has been linked to longevity—although the Frontiers in Bioscience-Landmark journal article I just linked to explains that increasing your VO2 max won’t increase your genetically determined lifespan. It just helps assure that you make it to the end of your pre-set limit—and that you do it in a positive, healthy way.

Here are a couple VO2 max charts, courtesy of The Cooper Institute:

On a final note, don’t beat yourself up in you can’t reach Greg LeMond’s freakish VO2 max of 92.5. Training can improve VO2 max, but about 50% of it is genetics. Some people just have powerful engines.

But who cares? I’m sure you have gifts that guys like three-time Tour de France winner LeMond don’t have. So shine on, you crazy diamond!