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How accurate is VO₂max tracking from wearables like WHOOP, Oura, and Garmin compared to lab tests (lactate threshold or spiroergometry)?

Karol Domagalski
Karol Domagalski

1 week ago (edited)

As my current fitness bottleneck is VO₂max, I’ve been adjusting my training to improve it.

To track progress accurately, I wanted to understand how reliable the VO₂max estimate from my WHOOP 4.0 is compared to a gold-standard lab test (spirometry with lactate threshold measurement). Here’s what I found:

My Results:
• WHOOP 4.0 estimate: 50 mL/kg/min
• Lab spiroergometry (bike ergometer): 45 mL/kg/min

Difference:
WHOOP appears to overestimate by about 10–15%, which aligns with what some studies and anecdotal reports suggest for wearables. That said, my WHOOP 5.0 just arrived, and I’ll recheck the values using the next-generation sensor hardware to see if there are any improvements or adjustments.

Important note:

My doctor mentioned that my true VO₂max might indeed be closer to 50 mL/kg/min, since the test was done on a bike ergometer. As I’m not a trained cyclist, my leg endurance may have limited the result.


Pro tip:
If you want the most accurate VO₂max reading, look for a spiro lab that offers testing on a treadmill or rowing ergometer in addition to a bike. These modalities engage more muscle groups, potentially leading to a higher and more holistic VO₂max reading, especially for runners, rowers, or hybrid athletes.

What about you?
Have you done a VO₂max lab test? How did it compare to your wearable (WHOOP, Garmin, Oura, Apple Watch, etc.)?

Would love to hear your experiences, especially if you tested on different machines or with different protocols.

@callum-parker
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Heiko Bartlog · 1 week ago

I will do a VO2max Spiro test this year in order to interpret the estimates by Whoop, Polar and the measurement at the Life Summit 2025 - and of course I will do it on a treadmill :)

Callum Parker · 1 week ago

I personally never measure my Vo2 Max. In my own instance, it's a vanity metric. My Garmin Venu 3 puts me at 70, my alltime high on Garmin is 72. That looks great in theory, but in reality I'm nowhere near my peak fitness. Running efficiency also plays a huge factor, hard to measure effectively.

I think for the general population what is most relevant is measuring your 5km time - can you run a 5km faster than 25 minutes? Good. Can you run faster than 20 minutes? Great. This is a very good predictor of cardiovascular health. You can use a different test for cycling, or swimming, whatever form of cardio you choose.

I don't think I'd ever think of Vo2 Max as a bottleneck to my training, especially with running. Just my perspective.

Floris Roltsch · 1 week ago

Had mine tested in Sept last year, also did a Cooper test to compare + my value from fitbit:

Spiro: 57.3

Fitbit: 57

Cooper: 58

Did the spiro on a treadmill and have been on a quite consistent running routine for very long time, so would not say it will be matching as much for everyone, in my case it did.

Got a new fitbit a few months back, which estimated my VO2max at 55, while my Cooper test estimate was 60.

Think +/- 10% variation from the real value or more should be expected from all these estimations, maybe more. However, given that you don’t really need much more accuracy, I might only do a spiro every 5 years or so to calibrate, otherwise rely on my trends from Cooper and fitbit.

Maximilian · 6 days ago

Appreciate your perspective on the topic. I certainly should do a test. Not sure if the result of my Garmin is believable. I do not measure that metric but it says that I have a VO2max of 55 at a Fitness age of 28.5. But again I have no context for these numbers.

Karol Domagalski · 3 days ago

Very interesting and thanks for sharing @heiko-bartlog, @callum-parker, @floris-roltsch and @maximilian.

I’ve decided to extend my VO₂max tracking by doing a regular Cooper test. I really like this non-digital approach as a way to cross-check against wearable and lab data.

As we all mentioned and agree, there’s probably a 10–15% error margin either way.

Just out of curiosity, some friends of mine are using it, has anyone here tested a chest strap like the Polar H10? Would be great to hear your experiences. Is it worth the money? And how accurate is it really?

Floris Roltsch · 3 days ago

@karol i don’t always wear my H10, only from time to time when I think my wrist-worn wearable is heavily off.

Based on my subjective experience, think it’s as accurate as it gets, but only found a small study that showed almost perfect alignment with ECG values for heart rate pre, during and post a cycling exercise:

https://pmc.ncbi.nlm.nih.gov/articles/PMC9459793/

Regularly saw a wrist-worn wearable being 20-30bpm off, not only during short intervals but also steady-state zone 2, so if you obsess over training at a certain heart rate, a chest strap would be recommended tbh.

Heiko Bartlog · 3 days ago (edited)

@karol what @floris-roltsch wrote: Polar H10 is ECG, gold standard for HR and HRV! And: bicep-worn wearables (Whoop, Amazfit Helio Strap, Polar Verity Sense, ...) are more accurate than wrist-worn ones.

Felix Lorenzen · 2 days ago

+1 to what @callum-parker aid.

To answer your question directly with the data I have:

My Apple VO2 max is currently around 55. Whoop showed a similar number (though I stopped wearing it).

I’d estimate it could be off by 5–10%.

Never done a spiro test.