Originally Posted by
Bob Ross
How do [Garmin] calculate VO2 max?
First, you need a power meter and heart monitor. Garmin has an algorithm that looks at your performance and estimates your VO2max from your ride data.
From the
Garmin website:
Assessing your VO2 max reliably from real-world activity data requires smart analytics capable of automatically recognizing the portions of your activity that truly reflect your abilities. This means, among other things, identifying and eliminating segments where your aerobic energy pathways are still warming up to increases in energy demand and those times when fatigue and cardiac drift are influencing your results.
The Garmin algorithm is based on one developed by
Firstbeat, which
report this about their method:
The method has been validated also with freely performed cycling by 29 cyclists whose pedaling power and heart rate were collected. The accuracy of the method when applied for cycling was 92% (MAPE [Mean Absolute Percentage Error] ~5%).