Garmin vs Oura Ring: VO2max compared
How Garmin and Oura Ring estimate your VO2max, what each needs from you, what else they show and what independent studies say about accuracy.
| Garmin | Oura Ring | |
|---|---|---|
| Called | VO2 Max. | Cardio Capacity (VO2 Max) |
| Algorithm | Garmin in-house, built on Firstbeat Analytics | Oura in-house |
| App | Garmin Connect | Oura app |
| From: Outdoor run | Yes | Not confirmed |
| From: Walk | Yes | Yes |
| From: Treadmill | No | No |
| From: Bike (power meter) | Yes | Not confirmed |
| From: Resting test | Not confirmed | Not confirmed |
| From: All-day data | Not confirmed | Not confirmed |
| Fitness age | Yes | Not confirmed |
| Race predictor | Yes | Not confirmed |
| Published accuracy studies | 5 | 0 |
| What you need to do | Run outdoors with GPS for at least 10 minutes at 70%+ of max heart rate, or ride steadily at high intensity for 20+ minutes with a power meter. Set up your user profile and max heart rate. | Gen3 or later ring with an active membership. Brisk 6-minute walk on a straight, level route, location services on, phone carried, phone battery above 20%. Not possible on a treadmill. Oura suggests a test about once a month. |
Key differences
- Fitness age: Garmin shows one (not confirmed for the other).
- Race predictions: Garmin has them.
- Accuracy evidence: we found 5 published studies for Garmin and 0 for Oura Ring.
How each one works
Garmin: Compares your heart rate (wrist or chest strap) with your GPS pace on outdoor runs, or with power from a power meter on rides. It learns over several activities, so early numbers may be off.
Oura Ring: A first estimate uses age, sex, height and weight (population averages). A guided 6-minute walking test then uses distance from phone GPS and ring heart rate to estimate VO2 max.
Which is better for VO2max?
For VO2max specifically, the best device is the one that sees your hardest efforts: if most of your training is outdoor running, both give an estimate (both use walk). If you cycle with a power meter, walk more than you run, or want a resting test, check those rows above. Whichever you choose, compare the number with itself over time and with the norms for your age.
Accuracy studies
Garmin
- Howard et al., J Med Eng Technol, 2026: Forerunner 265 overestimated VO2max (43.95 vs 41.10 ml/kg/min at start) but mean absolute percent error stayed under 10%.
- Engel et al., Eur J Appl Physiol, 2026: Forerunner 245 underestimated VO2max by about 4-5 ml/kg/min (MAPE 7.2-7.9%); error was larger in highly trained athletes (MAPE 9.4-10.4%).
- Carrier et al., Sensors, 2025: fēnix 6 VO2max estimates were judged accurate (MAPE 7.05%, concordance 0.73 vs 30 s lab average).
- Düking et al., J Sports Sci Med, 2024: Forerunner 245 in youth soccer players: MAPE 5.58% after one run and 1.06% after a second run.
- Passler et al., Int J Environ Res Public Health, 2019: Forerunner 920XT had a MAPE of 7.3% but significantly underestimated VO2max.
Oura Ring
No published, peer-reviewed validation found.
Frequently asked questions
Is Garmin or Oura Ring more accurate for VO2max?
Garmin has more published validation (5 vs 0 studies). Watch estimates are typically within several ml/kg/min of lab tests for groups, with larger individual errors, so use either one to track your trend.
Does Garmin measure VO2max from walk like Oura Ring?
Yes: both estimate from walk.
Which is better for VO2max: Garmin or Oura Ring?
Pick the one whose data sources match how you train: Garmin uses outdoor run, walk, bike (power meter); Oura Ring uses walk.
Built from official documentation (see each brand page for sources). Features vary by model and firmware. Garmin and Oura Ring are trademarks of their owners; VO2max Health is independent and not affiliated with either.