New Study shows the efficacy of SpO2 readings on the Apple Watch

Apple Watch Blood oxygen level accuracy

A new study designed by physicians and researchers based out of Italy evaluated the Apple Watch Series 6 for its accuracy in two key areas: Heart Rate and Oxygen Saturation (SpO2). The readings on the device were quite accurate.

The study results were published in the Journal of Clinical Medicine in March’2022.

Related reading

Apple’s oxygen saturation (SpO2) is put to the test in a new clinical study

Pulse oximetry is the most commonly used method to assess peripheral oxygen saturation (SpO2) in clinical practice. The smartwatch Apple Watch 6 was developed with a new sensor (that’s also on the Series 7 watch) and an app that allows taking on-demand readings of blood oxygen and background readings day and night.Apple Watch blood oxygen sensors

Apart from the optical heart sensor that aids in measuring heart rate and heart rhythm, the back crystal on the latest Apple Watch Series 7 features four clusters of green, red and infrared LEDs and four photodiodes used to measure blood oxygen levels with the Blood Oxygen app. 

The Series 6 used in this study was the first Apple Watch to feature this design that helped measure Blood Oxygen saturation levels

The smartwatch Apple Watch 6 was developed with a new sensor and an app that allows taking on-demand blood oxygen readings and background readings day and night. blood oxygen saturation SpO2 readings on Apple Watch

This Italian study recruited study participants with lung disease or cardiovascular disease and healthy subjects. A total of 265 subjects were screened for enrollment in this study.

The present study aimed to assess the feasibility and agreement of the Apple Watch 6 compared with a standard SpO2 monitoring system to assess normal and pathological oxygen saturation.

Researchers observed a strong positive correlation between the smartwatch and the standard commercial device in the evaluation of SpO2 measurements (r = 0.89, p < 0.0001) and HR measurements (r = 0.98, p < 0.0001). Apple Watch Blood Oxygen level accuracy

A very good concordance was found between SpO2 (bias, -0.2289; SD, 1.66; lower limit, -3.49; and upper limit, 3.04) and HR (bias, -0.1052; SD, 2.93; lower limit, -5.84; and upper limit, 5.63) measured by the smartwatch in comparison with the standard commercial device using Bland-Altman analysis.

Chronic respiratory failure is usually the final stage of several respiratory diseases such as chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, severe chest deformities, and acquired bronchiectasis. Patients living with hypoxemia, and often hypercapnia, present important physical, psychological and social impairments with significant deterioration in the quality of life.

Other studies have also looked at the accuracy of Apple Watch and SpO2 readings (Pilling and Cutaia22) and demonstrated that oximeters are viable and accurate with an acceptable level of motion artifacts. 

Results suggest ambulatory oximetry holds promise as a tool to monitor the adequacy of oxygen prescriptions in the outpatient with lung disease. 

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Sudz Niel Kar
I am a technologist with years of experience with Apple and wearOS products, have a BS in Computer Science and an MBA specializing in emerging tech, and owned the popular site AppleToolBox. In my day job, I advise Fortune 500 companies with their digital transformation strategies and also consult with numerous digital health startups in an advisory capacity. I'm VERY interested in exploring the digital health and fitness-tech evolution and keeping a close eye on patents, FDA approvals, strategic partnerships, and developments happening in the wearables and digital health sector. When I'm not writing or presenting, I run with my Apple Watch Ultra or Samsung Galaxy Watch and closely monitor my HRV and other recovery metrics.


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