COROS vs Apple Watch: VO2max compared
How COROS and Apple Watch estimate your VO2max, what each needs from you, what else they show and what independent studies say about accuracy.
| COROS | Apple Watch | |
|---|---|---|
| Called | VO2 Max | Cardio Fitness |
| Algorithm | In-house EvoLab | Apple in-house |
| App | COROS app | Health app (iPhone) |
| From: Outdoor run | Yes | Yes |
| From: Walk | Not confirmed | 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 | Yes |
| Fitness age | Not confirmed | Not confirmed |
| Race predictor | Yes | Not confirmed |
| Published accuracy studies | 0 | 3 |
| What you need to do | One continuous 25-minute outdoor run (Run or Track Run mode, no pauses) at or above 65% of heart rate reserve, then at least one such run every 90 days. Cycling: a steady 20+ minute ride with a power meter and heart rate. | Wear the watch for at least 24 hours, then do several Outdoor Walk, Outdoor Run or Hiking workouts in the Workout app. Fairly flat ground, good GPS and heart rate signal help. |
Key differences
- Race predictions: COROS has them.
- Accuracy evidence: we found 0 published studies for COROS and 3 for Apple Watch.
How each one works
COROS: Running VO2 max uses heart rate and pace from your recent outdoor runs. Since October 2026 there is also a cycling VO2 max from rides with power and heart rate data.
Apple Watch: Measures how hard your heart works (heart and motion sensors, GPS) during outdoor walks, runs and hikes, plus passive outdoor walking. It also uses your age, sex, weight, height and heart-rate medications.
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
COROS
No published, peer-reviewed validation found.
Apple Watch
- Lambe et al., Mayo Clin Proc Digit Health, 2026: Series 10 underestimated VO2max by 6.25 ml/kg/min on average; MAPE 13.2%; poor individual agreement.
- Lambe et al., PLoS One, 2025: Apple Watch underestimated VO2max by 6.07 ml/kg/min on average; MAPE 13.31%.
- Caserman et al., JMIR Biomed Eng, 2024: Series 7 estimate was lower than the lab value (41.37 vs 45.88 ml/kg/min); MAPE 15.79%, ICC 0.47.
Frequently asked questions
Is COROS or Apple Watch more accurate for VO2max?
Apple Watch has more published validation (3 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 COROS measure VO2max from outdoor run like Apple Watch?
Yes: both estimate from outdoor run.
Which is better for VO2max: COROS or Apple Watch?
Pick the one whose data sources match how you train: COROS uses outdoor run, bike (power meter); Apple Watch uses outdoor run, walk, all-day data.
Built from official documentation (see each brand page for sources). Features vary by model and firmware. COROS and Apple Watch are trademarks of their owners; VO2max Health is independent and not affiliated with either.