Oct 26, 2022 11:14:00

Research reveals that Apple Watch's blood oxygen sensor is as reliable as 'medical pulse oximeter'

Percutaneous arterial oxygen saturation (SpO ₂ ) is the percentage of hemoglobin bound to oxygen and is used as an index of respiration. There are many models of smart watches such as Apple Watch that are equipped with a function to measure this SpO ₂ , and it is possible to check it regularly. A study was announced that the Apple Watch's SpO ₂ measurement function is as reliable as a medical SpO ₂ measurement device, a pulse oximeter.

Commercial smartwatch with pulse oximeter detects short-time hypoxemia as well as standard medical-grade device: Validation study - PubMed
https://doi.org/10.1177/20552076221132127

How reliable is the Apple Watch's blood oxygen sensor?
https://9to5mac.com/2022/10/25/apple-watch-blood-oxygen-study/

A research team at the Department of Biomedical Engineering, Faculty of Biomedical Engineering, Czech Technical University investigated how well a commercially available smartwatch that measures SpO ₂ can detect hypoxemia compared to a medical pulse oximeter. The research team attached the Apple Watch Series 6 to the left wrist of 24 healthy subjects and the medical pulse oximeter Masimo Radical-7 to the left middle finger.

In addition, the research team had the subject wear a non-rebreathing mask, first inhale ambient air for 2 minutes, and then inhale hypoxic gas with an oxygen mixture ratio of 12% for the next 5 minutes, SpO ₂ decreased. Finally, _they were allowed to inhale ambient air until SpO2 returned to normal. SpO2 measurements were taken with _both the Apple Watch and the Masimo Radical-7 at 30 second intervals.

As a result, there was no bias in SpO ₂ values for all data points between Apple Watch and Masimo Radical-7. The difference between the Apple Watch and Masimo Radical-7 measurements was expected to be within ₆ % for SpO2 in the range of 90% to 100% and within ₈ % for SpO2 below 90%, but the actual results are also It seems to have fallen within the expected range.

The following is the actually measured data shown in the graph of SpO ₂ on the vertical axis and time on the horizontal axis. The solid line is the Apple Watch and the dotted line is the measurement result of Masimo Radical-7, showing that SpO ₂ can be detected with almost the same accuracy.

This means that the Apple Watch can reliably detect a reduced SpO ₂ state at the same level as a medical pulse oximeter. The research team evaluated that 'the technology used in Apple Watch is advanced enough to measure SpO ₂ even outside the hospital.'