That Apple is currently working on ways to measure blood pressure is no secret. Bloomberg’s Mark Gurman has been reporting on the possible addition of a blood pressure monitor for Apple Watch going back at least to April 2022.Gurman predicted that Apple would introduce this feature in 2024, but that didn’t materialize.
Now the U.S. Patent Office published a patent application of Apple’s relating to an Apple Watch with Blood Pressure monitoring.
Apple notes that it can be difficult to precisely determine conventional blood pressure parameters, such as systolic and diastolic blood pressures, using oscillometry measurement techniques. It may be desirable to more precisely determine events associated with a blood pressure measurement, including the closing and/or opening of a blood vessel during a compression measurement.
Apple’s patent covers a blood pressure measurement device that uses a liquid filled sensing chamber to measure blood pressure of a user.
An inflatable chamber is first filled, which, together with a sensing chamber and a pressure sensor, work to detect the resulting ‘vibrations’ that occur in the user’s blood flow. In simple terms: Blood pressure is the externally applied pressure required to stop blood flow. Korotkoff sounds, the sounds or ‘vibrations’ that are emitted when pressure is applied to blood flow via a non-invasive procedure, can then be measured.
The patent mentions that the chamber is filled with liquid – what advantages liquid offers instead of air is not immediately clear, as liquids, unlike gases (and ultimately air) are considered incompressible.
The patent was created by Apple hardware engineer Caleb Han, an 11-year veteran.But as always, just because Apple is patenting a particular technology doesn’t necessarily mean it will be implemented in the next Apple Watch, or even at all.