VO₂max: How do You Measure and Improve it?

VO₂max is one of the most powerful predictors of health status: how do you measure and improve it?

VO₂max is one of the most powerful predictors of health status, and is independently associated with protection from disease and death. If you are new to VO₂max, start here:

This is Part 2 of the VO₂max series.

What is the Gold Standard Measure of VO₂max?

The gold standard method of VO₂max (maximum rate of oxygen consumption) determination requires maximal exercise testing using indirect calorimetry (ie. measurement of oxygen consumption via a facemask) on at least two different modalities (e.g. running and cycling) on separate days. Some people may be able to achieve higher oxygen consumption rates on a bike, while most can achieve a higher oxygen consumption rate on a treadmill test.

While there are numerous protocols, essentially all tests gradually increase exercise intensity (whether it is wattage/resistance on the bike or incline/speed on the treadmill) until the participant achieves a plateau in oxygen consumption despite an increase in exercise duration. The rate of oxygen consumption is captured every 20-60 seconds, and the peak oxygen consumption reported gives you the VO₂peak score. For most applications outside of the ex phys lab, VO₂peak and VO₂max are used interchangeably.

When I was first certified by the American College of Sports Medicine (ACSM), I learned of the at least two criteria that should be met to confirm maximal effort:

• VO₂ Plateau (≤150 mL·min⁻¹ increase)

• Heart Rate (HR) within ±10 bpm of Age-Predicted Maximum

• Respiratory Exchange Ratio (RER) ≥ 1.10

• Rating of Perceived Exertion (RPE) ≥ 17 (Borg 6–20 Scale)

• Blood Lactate ≥ 8 mmol/L (when measured)

• Volitional Fatigue (Inability to Continue)

This combination of objective and subjective metrics just suggests that the test subject just needs to be pushing as hard as possible to be a “true max.”

VO₂max can be calculated in absolute (L/min.) or relative units (mL/kg/min.) of oxygen. VO₂max relative to body weight is more important, and takes into consideration body composition. Since body weight is in the denominator, the lower the body weight, the higher one’s VO₂max.

Shown below is a typical graph of what your heart rate and oxygen consumption looks like during a maximal exercise test. The highest circle is the key metric.

This also shows why during-exercise heart rate serves as a great, but imperfect, data point that can feed into models that estimate your VO₂max.

Review of Methods for Measuring/Estimating VO₂max

While the laboratory is the gold standard method for determining VO₂max, there are many simpler and more scalable estimates.

The laboratory requires specialized equipment, frequent calibration and maintenance (if you care about accuracy), trained staff, and a willing participant to carve out the time in their day to exercise completely to exhaustion.

One of the next best alternatives, that requires no equipment, is the Cooper 12 minute all-out running test. Developed over 50 years ago, this simple test can easily calculate your VO2max with relatively high accuracy. But still requires you to exercise to maximal exhaustion.

Additionally, the Whoop, Apple Watch, and many other wearables can predict your VO₂max with some degree of certainty, typically based on your resting and/or activity heart rate. These predictions get better with more data (on yourself and at the population level).

Finally, there is a last tier which can simply estimate your VO₂max from your sex, weight, age, etc. I bucket this estimate the same way that I do as BMI as a metric for body composition— at the population level it is decent, but the individual level variability (or meaninglessness) can be enormous.

How do you improve your VO₂max?

Before getting into the specifics, lets think from first principles. VO₂max represents your body’s maximal capacity to use oxygen (integrating the functions of your lung, heart, blood, muscles, and mitochondria). To improve the maximal capacity of anything, you need to challenge the system. In response to the challenge, the system adapts.

Challenging your body’s capacity (elevating heart rate, breathing rate, blood flow to muscles, and oxygen extraction), then adapting to that challenge, is how to increase your VO₂max.

Now we can get more specific. When using VO₂max calculated relative to body weight (mL/kg/min.), the first way to increase VO₂max is to lower the denominator— that is, lose weight. Since the oxygen consumption during maximal exercise is largely driven by muscle and heart mitochondria, the more direct way is to lose fat.

Now, beyond losing weight, there are numerous exercise training programs that have been developed to increase VO₂max. When looking systematically at 37 studies there is a lot of variability in the protocols. You can see this wide distribution below:

Bacon et al 2013

There are two points to make from this analysis:

• The highest increases in VO₂max are from protocols that include high intensity interval training (HIIT)

• That outlier all the way to the right, is a BRUTAL protocol (but only 40 min a day)

  • Weekly VO₂max testing to determine your high intensity interval

  • 6 days a week of exercising as hard as you can for 40 minutes

    • 3 days run as far as you can

    • 3 days of intervals on the bike- six 5 minute intervals at the intensity at which you achieved your VO₂max, separated by 2 minutes at 50%

  • This protocol led to an average increase in VO₂max of 38% in just 10 weeks

However, for most people, gradual weight loss accompanied by gradual improvements in fitness can lead to large changes in this potent biomarker.

The Future of VO₂max Trainability

As interest in and understanding of VO₂max continues to improve (see Google Trends), we will begin to have large real-world datasets tied to people’s VO₂max scores. This will serve as a large-scale n-of-1 database to truly understand how we can personalize people’s protocols to maximize the benefits of exercise, nutrition, and other interventions.

How do you measure your VO₂max?