Key takeaways
Garmin estimates VO2max from heart rate against pace on outdoor GPS runs of 10 minutes or more, or from power on rides with a power meter
The colour gauge runs from red (Poor) to purple (Superior), based on Cooper Institute percentiles for your age and sex
Studies find Garmin estimates fairly close for moderately trained runners but less accurate in very fit athletes, so judge the trend, not a single reading
Garmin watches show VO2max as a number, a word and a coloured gauge. The number is an estimate, not a measurement, and it comes from the link between your heart rate and your speed. Here is how to read it, how far to trust it and what actually moves it.
How Garmin estimates VO2 max
The algorithm comes from Firstbeat Analytics, and the ratings from The Cooper Institute. According to Garmin's Forerunner 965 manual, you need wrist-based heart rate or a compatible chest strap, and then:
- Running: run outdoors with GPS at moderate or high intensity, reaching at least 70% of your maximum heart rate, for at least 10 minutes.
- Cycling: ride with a power meter at a steady, high intensity for at least 20 minutes.
Running and cycling have separate estimates. The estimate may seem off at first; the watch needs a few runs to learn your performance. Complete your user profile and set your real maximum heart rate.
VO2 max Garmin: where to find it
On most watches, save an outdoor run and press up or down to scroll through the performance measurements. Many models also have a VO2 max glance or widget you can add. Your number appears with a description and a position on the colour gauge. Garmin says your Garmin Connect account shows more detail, including where you rank for your age and sex. Exact menus differ by model, so check your watch's manual.
Garmin VO2 max chart and colours
The gauge has five colours: purple = Superior, blue = Excellent, green = Good, orange = Fair, red = Poor. Below are the values from Garmin's standard ratings table, in ml/kg/min. Each number is the value at that percentile; Poor is anything below the Fair value.
| Rating (colour) | Percentile | Men 20–29 | Men 40–49 | Men 60–69 | Women 20–29 | Women 40–49 | Women 60–69 |
|---|---|---|---|---|---|---|---|
| Superior (purple) | 95th | 55.4 | 52.5 | 45.7 | 49.6 | 45.3 | 37.8 |
| Excellent (blue) | 80th | 51.1 | 46.4 | 39.5 | 43.9 | 39.7 | 33.0 |
| Good (green) | 60th | 45.4 | 42.4 | 35.5 | 39.5 | 36.3 | 30.0 |
| Fair (orange) | 40th | 41.7 | 38.5 | 32.3 | 36.1 | 33.0 | 27.5 |
| Poor (red) | below 40th | <41.7 | <38.5 | <32.3 | <36.1 | <33.0 | <27.5 |
So what VO2 max is purple on Garmin? For a man in his 20s, about 55 or more; for a woman in her 20s, about 50 or more. "Superior on Garmin" puts you in roughly the top 5% for your age and sex. For all ages and both sexes, see our VO2max chart and VO2max norms by age and sex.
VO2 max Garmin accuracy
- Firstbeat's white paper reports about 95% accuracy for running (an average error of about 5%), from 2,690 runs by 79 runners. That is company data.
- Engel et al., 2026, tested the Forerunner 245 against lab gas analysis in 35 endurance athletes. Error was about 2.8% in moderately trained athletes but 9.4% in highly trained ones (VO2max above 60), whose values were underestimated.
- The 2022 INTERLIVE meta-analysis found exercise-based watch estimates close on average for groups, with large errors for some individuals.
In short, Garmin is a good trend tracker for most recreational runners and less reliable at the top end. More in how accurate is your watch's VO2max estimate?
Why did my Garmin VO2max drop?
The estimate falls whenever your heart rate is higher than expected for your pace:
- Heat and altitude. Supported watches apply heat and altitude acclimation corrections to VO2max above 22°C (72°F) and 800 m (2,625 ft); heat correction needs GPS activities and weather data from your phone. See heat training and altitude training.
- Fatigue, illness, poor sleep or alcohol, which raise heart rate. See resting heart rate, HRV and recovery.
- Hills, trails, wind or poor GPS. On some watches, such as the Forerunner 965, you can stop trail and ultra runs from counting: hold the menu button, then Activities & Apps > Trail Run or Ultra Run > activity settings > Record VO2 Max. > Off.
- Optical heart-rate errors from a loose strap or cold wrist. A chest strap helps.
- Profile changes: higher weight or a wrong maximum heart rate. See VO2max and body weight.
A real drop is more likely after several weeks off; see detraining: how fast you lose VO2max.
How to increase VO2 max on Garmin
Garmin's own advice is to include high-intensity workouts, allow recovery, and vary your training. In practice:
- One or two interval sessions a week, such as the Norwegian 4×4.
- Plenty of easy running, roughly 80/20. Set zones with the heart rate zone calculator.
- Run outdoors with GPS on flat routes so the watch gets clean data.
Expect a plateau after years of training; that is normal.
Fitness age on Garmin
Fitness age compares your fitness with people of the same sex. Garmin's vívoactive 5 manual says it uses your age, BMI (or body fat from an Index scale), resting heart rate and vigorous activity history. On that watch: Settings > User Profile > Fitness Age. Garmin suggests at least 5 vigorous intensity minutes within a 30-minute workout, a lower resting heart rate and lower body fat to bring it down.
Fitness age decreased on Garmin? That is good news: a lower fitness age means your fitness looks like that of a younger person. If it went up, check the same factors: fewer vigorous minutes, a higher resting heart rate or weight gain. Compare with our fitness age calculator, VO2max calculator or VO2max running calculator.
Garmin, Firstbeat and The Cooper Institute are trademarks of their respective owners. VO2max Health is independent and not affiliated with or endorsed by any of them.
Frequently asked questions
Where do I find VO2 max on Garmin?
On most watches, save an outdoor run and scroll through the performance measurements, or open the VO2 max glance or widget. Your Garmin Connect account shows more detail, including where you rank for your age and sex.
What VO2 max is purple on Garmin?
Purple means Superior, the top rating, at or above the 95th percentile of Cooper Institute data. For men aged 20 to 29 that is about 55.4 ml/kg/min and for women about 49.6.
Is Garmin VO2 max accurate?
Firstbeat, which supplies the algorithm, reports about 95% accuracy for running. An independent 2026 study found errors of about 3% in moderately trained athletes but about 9% in highly trained ones, whose VO2max was underestimated.
Why did my Garmin VO2 max drop?
Anything that raises your heart rate at a given pace lowers the estimate: heat, humidity, altitude, fatigue, illness, poor sleep, hills or trails, or a bad optical heart-rate reading. Weight gain or a wrong max heart rate can also lower it. A drop over one or two runs rarely means you lost fitness.
Sources
- Garmin. Forerunner 965 Owner's Manual: About VO2 Max. Estimates.
- Garmin. Forerunner 965 Owner's Manual: VO2 Max. Standard Ratings (data from The Cooper Institute).
- Garmin. Forerunner 970 Owner's Manual: Heat and Altitude Performance Acclimation.
- Garmin. vívoactive 5 Owner's Manual: Viewing Your Fitness Age.
- Garmin Blog. What is your Garmin fitness age? How can you lower it?
- Garmin Blog. Why isn't my VO2 max increasing? Tips for improving faster
- Firstbeat. Automated fitness level (VO2max) estimation with heart rate and speed data, white paper, 2017.
- Engel FA, et al. Validity of VO2max estimates from the Forerunner 245 smartwatch in highly vs. moderately trained endurance athletes. Eur J Appl Physiol, 2026.
- Molina-Garcia P, et al. Validity of estimating the maximal oxygen consumption by consumer wearables: a systematic review with meta-analysis and expert statement of the INTERLIVE network. Sports Med, 2022.