VO2Max Estimate
VO2max is the maximum rate at which your systems can deliver oxygen to the working muscles, and it is often the primary measure of aerobic fitness. VO2max can be improved with training, but several factors influence this process (e.g. current fitness, sex, age, and the type of training and activity).
VO2max is the “ceiling” for aerobic energy production.
The best way to measure VO2max is via graded exercise test in a laboratory, where your respiratory gases can be directly measured and analyzed using indirect calorimetry. A laboratory-based VO2max test is not always feasible, and several prediction equations have been established to estimate VO2max.
Garmin devices use a prediction algorithm for estimating VO2max. For the estimation of running VO2max, you must use the Run training profile. The other requirements are:
- Activity must be at least 10 minutes in duration and recorded outdoors using GPS
- Heart rate data must be available (either from wrist or chest strap)
- Heart rate must be elevated to at least 70% of your maximal heart rate for at least 10 minutes without a break
Garmin also provides VO2max estimates for cycling in both the watches and cycling computers, with minor adjustments compared to running:
- Cycling training profile must be selected, and the activity last at least 20 minutes without breaks
- Heart rate data must be available (either from wrist or chest strap)
- Heart rate must be elevated to at least 70% of your maximal heart rate for at least 20 minutes without a break
- Power meter is required
Is the VO2max estimate accurate?
It is indeed an estimate and should be viewed with caution! Studies have compared the Garmin estimates against the actual, measured values with indirect calorimetry and found significant differences between the values. One should not base their training off the Garmin VO2max metric as it seems like the algorithm requires daily high intensity exercise for the maintenance and improvement of the VO2max value, which may lead to overtraining and injury. In real life, your VO2max does not fluctuate that much – it takes time to see changes in either direction – one slower or faster run will neither break you or make you!.
References
ACSM’s Guidelines for Exercise Testing and Prescription: Seventh Edition (2006, p. 79)
Kraft, G. L., & Roberts, R. A. (2017). Validation of the Garmin Forerunner 920XT Fitness Watch VO2peak Test. International Journal for Innovation Education and Research, 5(2), 63–69.
Passler, S., Bohrer, J., Blöchinger, L., & Senner, V. (2019). Validity of Wrist-Worn Activity Trackers for Estimating VO2max and Energy Expenditure. International Journal of Environmental Research and Public Health, 16(17), 3037–.
Snyder, Nikolas C.; Willoughby, Courtney A.; Smith, Bryan K. Accuracy of Garmin and Polar Smart Watches to Predict VO2max, Medicine & Science in Sports & Exercise: May 2017 – Volume 49 – Issue 5S – p 761.
Snyder, N.C, Willoughby C.A, and Smith, K.B. (2019). Comparison of the Polar V800 and the Garmin Forerunner 230 to Predict V[Combining Dot Above]O2max. The Journal of Strength and Conditioning Research: Online.
