The Apple Watch spO<sub>2</sub> sensor and outliers in healthy users.

Schröder, Christina; Förster, Robert; Zwahlen, Daniel R; Windisch, Paul · NPJ Digit Med · 2023

cross_sectional · Level IV

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Abstract

It is unclear how frequently the Apple Watch produces spO<sub>2</sub> measurements outside of the normal range in healthy individuals at rest. We conducted a head-to-head comparison in 38 healthy individuals between two watches and two medical-grade pulse oximeters. Fourteen percent of watch measurements yielded spO<sub>2</sub> values below 95%, with no values below 92%. Results suggest that outliers measured by the watch should not be a cause for concern in otherwise healthy individuals.