Suunto vs Polar: VO2max compared
How Suunto and Polar estimate your VO2max, what each needs from you, what else they show and what independent studies say about accuracy.
| Suunto | Polar | |
|---|---|---|
| Called | Fitness level (VO2max) | VO2max (Fitness Test, Walking Test) and Running Index |
| Algorithm | Not named in current Suunto manuals | Polar in-house |
| App | Suunto app | Polar Flow |
| From: Outdoor run | Yes | Yes |
| From: Walk | Yes | Yes |
| From: Treadmill | Not confirmed | Not confirmed |
| From: Bike (power meter) | Not confirmed | Yes |
| From: Resting test | Not confirmed | Yes |
| From: All-day data | Not confirmed | Not confirmed |
| Fitness age | Yes | Not confirmed |
| Race predictor | Yes | Yes |
| Published accuracy studies | 0 | 4 |
| What you need to do | Record a run or walk of at least 15 minutes with heart rate. On the Suunto Run the manual mentions runs only. | 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
- Fitness age: Suunto shows one (not confirmed for the other).
- Accuracy evidence: we found 0 published studies for Suunto and 4 for Polar.
How each one works
Suunto: The watch reads your heart rate response during recorded runs and walks, together with pace and movement data. Past runs and walks are also used, so the estimate gets better as you record more.
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, 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
Suunto
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 Suunto 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 Suunto measure VO2max from outdoor run like Polar?
Yes: both estimate from outdoor run, walk.
Which is better for VO2max: Suunto or Polar?
Pick the one whose data sources match how you train: Suunto uses outdoor run, walk; 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. Suunto and Polar are trademarks of their owners; VO2max Health is independent and not affiliated with either.