Is Garmin VO₂ max accurate.

By Coach Hunter Bennett

As the popularity of running has increased, there has been a rise in the number of people using the fitness metrics from their smart watch – with the big one being VO₂max.

These VO₂max measures are supposed to help you track your fitness.

But just how accurate is this metric, and should you rely on it?

Let’s dive into what VO₂max is, how Garmin calculates it, and what you should know about its accuracy.

What Is Your VO2 Max?

Your VO₂max refers to your “maximal oxygen uptake,” and it is a measurement of the maximum amount of oxygen your body can use during intense exercise.

It is arguably the best measure we have of your aerobic fitness.

The higher your VO₂max, the more oxygen your body can use to create energy, allowing you to sustain higher-intensity exercise for longer. This metric is often expressed in millilitres of oxygen per kilogram of body weight per minute (ml/kg/min).

To give you some perspective, a sedentary person might have a VO₂max of around 30 ml/kg/min, while elite endurance athletes can have values of 80 ml/kg/min, or in some cases even higher.

The gold standard for measuring VO₂max is through a laboratory test, where you wear a mask and perform progressively harder exercise on a treadmill or bike until you reach exhaustion. This mask measures the air you expire, providing a direct measure of the amount of oxygen your body is using to produce energy.

However, lab testing is time-consuming, expensive, and inconvenient — which is where wearable devices like Garmin come in.

How Does Garmin Calculate VO2 Max?

Garmin devices (and other smart watches) estimate VO₂max based on your heart rate and movement data during exercise (mainly runs or bike rides), as well as your age, gender, heart rate variability, and pace data.

For a Garmin watch to calculate your VO₂max, it generally requires:

• A consistent heart rate reading: It’s best to use a chest strap for more accurate heart rate data, though the wrist-based monitor can work as well.
• GPS data: For running, Garmin tracks your pace and compares it with your heart rate. A higher pace with a lower heart rate suggests a more efficient cardiovascular system, indicating a higher VO₂max.

These data points get fed through Garmin’s secret algorithm, which estimates your VO₂max.

Is Garmin VO2 Max Accurate?

Now for the big question: can you trust Garmin’s VO₂max estimates?

The answer is…sort of.

When compared to lab-based studies, some Garmin watches have been shown to overestimate VO₂max compared, while others have been shown to underestimate.

This finding is consistent with other brands of smart watch and their ability to estimate VO₂max.

For example, research on the Garmin Fenix 3 would suggest that if it tells you your VO₂max is 50, it might actually be closer to 45.

However, there is a silver lining here.

While they may not be super accurate, these seem to be closely correlated with lab based measures. This means that while they may over or underestimate your true VO₂max, they do so consistently – which makes them reasonable for tracking changes over time.

So, if your Garmin watch shows an increase in VO₂max over time, you are probably getting fitter.

Is Garmin VO2 Max Accurate? Final Thoughts.

If you’re training for an event or just working to improve your fitness, Garmin’s VO₂max estimate can be a useful guide, especially for spotting trends.

If it’s increasing over time, you’re probably getting fitter. If it’s not moving or going down, you may need to tweak your training.

But if you need a truly precise number for VO₂max, a lab test is still your best bet.

And if you are keen to start strength training but are not sure where to start, check out some of our programs or feel free to contact us for more information.