Garmin vs WHOOP: VO2max compared
How Garmin and WHOOP estimate your VO2max, what each needs from you, what else they show and what independent studies say about accuracy.
| Garmin | WHOOP | |
|---|---|---|
| Called | VO2 Max. | VO2 Max |
| Algorithm | Garmin in-house, built on Firstbeat Analytics | WHOOP in-house machine-learning model |
| App | Garmin Connect | WHOOP app |
| From: Outdoor run | Yes | Yes |
| From: Walk | Yes | Not confirmed |
| From: Treadmill | No | Not confirmed |
| From: Bike (power meter) | Yes | Not confirmed |
| From: Resting test | Not confirmed | Not confirmed |
| From: All-day data | Not confirmed | Yes |
| 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. | At least 14 recoveries (sleeps) in the last 21 days. Optional: a 15+ min outdoor run with Track Route on (in the last 90 days) and an up-to-date weight. |
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 WHOOP.
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.
WHOOP: A passive model uses resting physiology during sleep, activity volume and intensity, sleep habits and profile data. An outdoor run with phone GPS adds pace vs heart rate, and a lab result you enter can anchor future estimates.
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 outdoor run). 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.
WHOOP
No published, peer-reviewed validation found.
Frequently asked questions
Is Garmin or WHOOP 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 outdoor run like WHOOP?
Yes: both estimate from outdoor run.
Which is better for VO2max: Garmin or WHOOP?
Pick the one whose data sources match how you train: Garmin uses outdoor run, walk, bike (power meter); WHOOP uses outdoor run, all-day data.
Built from official documentation (see each brand page for sources). Features vary by model and firmware. Garmin and WHOOP are trademarks of their owners; VO2max Health is independent and not affiliated with either.