Peter Attia: The VO₂ Accuracy of Wearables | Peter Attia

Key Takeaways

• Ignore VO₂ max estimates from wearables – They don’t measure gas exchange and rely on error-prone algorithms.
• Don’t trust wrist-based heart rate data – Optical sensors are often inaccurate, with readings drifting significantly.
• Avoid relying on passive estimates – Wearables don’t let you control when or how VO₂ max is measured, leading to skewed results (e.g., Zone 2 training falsely lowering estimates).
• Expect large margins of error – A wearable VO₂ max reading of 52 could realistically be anywhere between 42 and 62.

Notable Quotes

“If the watch tells you your VO₂ max is 52, it could be 42, it could be 62, and I’ve seen that big a swing on the devices.”

Bottom Line

Use wearables for general trends, but don’t rely on their VO₂ max estimates for precision – seek lab-based testing if accuracy matters.

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