How Accurate Is Garmin Vo2 Max?

Cyclists and runners tend to get very excited about performance stats.  Ultimately, everything they are doing is about improving and gaining fitness.

How Accurate Is Garmin Vo2 Max

When it comes to a device that can shed some light on physical capabilities, it’s seen as very exciting.

Ask any professional road cyclist, and they would have had their fair share of Garmin stats chats with fellow cyclists.

Many have genuine power meters on their bikes which give absolute wattage measurements which can be correlated to very accurate Vo2 max predictions. 

Of course, the only way to get a genuine Vo2 max reading is to go to a specialist lab and get hooked up to machines that measure your oxygen flow over a set time.

This test is challenging for a number of reasons. It’s indoors and often hot, you have a face mask with a tube attached restricting ease of breathing, wires stuck to your body, and, of course, you are riding until exhaustion upping the power every 45 seconds. 

Most people can’t afford to undergo professional testing so Garmin has come up with a clever way to give predictions to athletes. 

In this article, we will look at how Garmin predicts your Vo2 max of basic measurements and how accurate it really is. 

What Is Vo2 Max?

How Accurate Is Garmin Vo2 Max

To put it simply, Vo2 max is how much oxygen your body can take in during exercise. More precisely, it is the maximum rate of oxygen your body is able to process during maximum exercise. 

When we breathe in oxygen, our lungs absorb it and transform it into adenosine triphosphate, also known as ATP.

ATP powers human cells and helps expel harmful by-products such as CO2 which is subsequently exhaled to reduce lactic acid buildup.

The greater your Vo2 max, the more oxygen your body can absorb allowing your body to produce ATP most effectively. 

How Does Garmin Calculate Your Vo2 Max? 

Garmin uses the Firstbeat Fitness test to help calculate Vo2 max as accurately as possible. For this to be accurate, athletes must provide certain information as accurately as possible. Such as:

  • Your age and fitness level
  • Data is collected from workouts and heart rate parameters taken from a heart rate strap and speed
  • Information is categorized into different heart rate zones based on unique athletes’ information
  • Continuous activity overtime allows Garmin to build up accuracy 
  • The most consistent information is then used to determine Vo2 max through heart rate and speed information

Vo2 Max Calculation In More Depth

How Accurate Is Garmin Vo2 Max

The calculations used are listed below:

  • Walking: Estimated Vo2 (ml/kg/min)=1.78*16.67[tan(inclination)+0.073]
  • Running on flat ground: Estimated Vo2 max (ml/kg/min)=3.5 speed
  • Hilly Running Terrain: Estimated Vo2 (ml/kg/min) = 3.33*speed+15*tan(inclination)*speed+3.5
  • Rowing (Indoors): Estimated Vo2 (ml/kg/min)=(14.72*Power+250.39)/person’s weight
  • Cycling: Estimated Vo2 (ml/kg/min)=(12.35*Power+300)/person’s weight

Garmin will then use your heart rate zones to calculate your efforts and therefore your Vo2 max. 

Is It Accurate?

Tests were carried out at Firstbeat Analytics to determine the accuracy of the Vo2 max scores.

In one study, they used 2695 runs from 80 different runners that had their vo2 max tests 5 times during a set period of 6-9 months.

The Garmin Vo2 max accuracy was quite good considering its lack of absolute data, coming back with 95% correctness with an error margin of less than 3.5ml/kg/min.

This sounds amazing I know, but the tested subjects had very accurate parameters regarding their heart rate parameters.

If a user gives incorrect HR info but just a few percent then the Vo2 max predictions will have a far greater scope for error and inaccurate results. 

Note, it’s very important to do an accurate max heart rate test to allow the Vo2 max predictions to be as accurate as possible. 

Garmin Watches That Measure Vo2 Max

How Accurate Is Garmin Vo2 Max
  • Garmin Vivoactive
  • Garmin Forerunner
  • Garmin Fēnix 6S
  • Garmin Edge 520


As discussed above, getting a professional Vo2 max test isn’t something most amateur athletes can justify.

It’s a useful statistic to know, but, ultimately, it’s something that is harder to change than other aspects of fitness, so many athletes don’t spend too much time worrying about it. 

Some exceptional athletes have surprisingly low Vo2 max scores, and some athletes who have amazingly high scores don’t tend to correspond in their performance.

It isn’t the be-all and end-all of athletic performance, there are many other complex factors such as the ability to recover quickly from efforts, and fast and slow twitch muscle fiber distribution and functionality. 

Garmin has developed a solid system using Firstbeat Fitness and Analytics to determine a surprisingly accurate measurement of an athlete’s Vo2 max whether you are a cyclist, runner, or rower.

What’s very important to remember is the accuracy of your heart rate parameters.

If you don’t undergo a proper max heart rate test, or fail to exert yourself fully to find out your maximum heart rate, this will affect the parameters Garmin uses to accurately predict your Vo2 max. 

It also uses the consistency of workouts and parameters over time to develop accurate readings therefore it is important to allow for this before expecting an accurate Vo2 score.

This is of paramount importance when determining whether the Garmin Vo2 max feature is accurate. 

I hope this article helps shed some light on the functionality and effectiveness of the Garmin Vo2 max feature. Happy training!

Megan Rinzel
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