COROS vs Polar: VO2max compared
How COROS and Polar estimate your VO2max, what each needs from you, what else they show and what independent studies say about accuracy.
| COROS | Polar | |
|---|---|---|
| Called | VO2 Max | VO2max (Fitness Test, Walking Test) and Running Index |
| Algorithm | In-house EvoLab | Polar in-house |
| App | COROS app | Polar Flow |
| From: Outdoor run | Yes | Yes |
| From: Walk | Not confirmed | Yes |
| From: Treadmill | No | Not confirmed |
| From: Bike (power meter) | Yes | Yes |
| From: Resting test | Not confirmed | Yes |
| From: All-day data | Not confirmed | Not confirmed |
| Fitness age | Not confirmed | Not confirmed |
| Race predictor | Yes | Yes |
| Published accuracy studies | 0 | 4 |
| 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. | Running Index: run at least 12 minutes at 6 km/h or faster with heart rate and GPS (or a stride sensor). Fitness Test: lie still for about 5 minutes. Walking Test: 15 minutes of brisk outdoor walking above 65% of max heart rate. |
Key differences
- Accuracy evidence: we found 0 published studies for COROS and 4 for Polar.
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.
Polar: Several routes: a 5-minute resting Fitness Test (resting heart rate, HRV, age, sex, height, weight, training background), Running Index after runs (heart rate vs speed), a 15-minute Walking Test, and running and cycling performance tests.
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, bike (power meter)). 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.
Polar
- Dakule et al., J Funct Morphol Kinesiol, 2025: In 50 masters basketball players aged 51-81, the Polar OwnIndex (Fitness Test) substantially overestimated VO2max with poor agreement.
- Cooper & Shafer, Int J Exerc Sci, 2019: Polar A300 Fitness Test correlated moderately with treadmill VO2max (r = 0.655) and was repeatable (test-retest r = 0.907).
- Köteles et al., Acta Physiol Hung, 2015: OwnIndex on an RS-400 was driven mainly by self-reported activity level (R² = 0.883); authors call it not an appropriate measure of aerobic fitness.
- Niemeyer, Leipziger sportwissenschaftliche Beiträge, 2013: Running Index correlated with lab VO2max in 18 male runners (r = 0.60).
Frequently asked questions
Is COROS or Polar more accurate for VO2max?
Polar has more published validation (4 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 Polar?
Yes: both estimate from outdoor run, bike (power meter).
Which is better for VO2max: COROS or Polar?
Pick the one whose data sources match how you train: COROS uses outdoor run, bike (power meter); Polar uses outdoor run, walk, bike (power meter), resting test.
Built from official documentation (see each brand page for sources). Features vary by model and firmware. COROS and Polar are trademarks of their owners; VO2max Health is independent and not affiliated with either.