Your next Garmin could have an updated high-tech blood oxygen sensor

Garmin has applied to patent a new way for smartwatches to measure blood oxygen saturation levels, or SpO2. Published on May 12, the patent was originally filed in 2020, which could imply that the technology might soon be on the way.

Most wrist-mounted pulse oximeters currently used by Garmin watches (as well as by rivals such as the Fitbit Charge 5) use a combination of red and infrared light projected onto your wrist from the back of the smartwatch. This can estimate the percentage of oxygenated blood in your body, and indicate if your SpO2 levels are normal.

On Garmin’s current Pulse Ox (opens in new tab) page, it says: “If you think about your blood as a train and oxygen as the passengers on that train, a pulse oximeter is telling you how crowded the train is compared to maximum capacity. When every seat in the train has a passenger sitting in it, then the train is operating at 100% capacity.”

However, the published patentfirst picked up by outdoors website Adventure, differs from current methods of testing by adding a third LED into the mix, this one also emitting red light at a different wavelength in order to get a third reading. By comparing this third reading to the first two, the watch will be “calculating a second estimated in-blood percentage of oxygenated hemoglobin based on a comparison between the second and third digital values”, in order to ensure the measurement is more accurate.

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