Apple Watch blood pressure monitoring tech revealed in patent

(Image credit: Future)

Apple Watch blood pressure technology has been rumored for years
A new patent could reveal how the company might achieve it
It points to a liquid-filled sensor housed in the strap of your Apple Watch

A new Apple Watch patent published on March 18 has revealed the company is working on blood pressure monitoring technology that leverages a liquid-filled sensor.

First spotted by PatentlyApple, the patent is titled Blood pressure monitoring system including a liquid-filled sensor and points to one possible way in which Apple could crack the hallowed blood pressure sensing it has been trying to figure out for years.

Apple is expected to debut a new Apple Watch Ultra 3 and Apple Watch Series 11 in September. These will no doubt be the best Apple Watch models we've seen to date and are tipped to include blood pressure monitoring of some sort.

Apple's blood pressure patent

Apple Watch blood pressure patent — (Image credit: Apple / USPTO)

The patent describes the current methods for monitoring blood pressure, namely an inflatable cuff that restricts blood flow to determine pressure. As Apple notes, accuracy can vary based on inflation and deflation rates, and the design of the cuff itself.

Apple's patent seeks to increase accuracy and precision and describes a blood pressure monitoring device featuring a strap and an air pump, as well as an inflatable chamber. It also includes a pressure-sensing chamber coupled to the inflatable chamber, and housed between the inflatable chamber and the user.

Apple says this sensor could include a liquid volume, as well as a pressure-sensing device configured to detect blood pressure.

The patent contains the usual dense mire of patent language, but the upshot is clear. Apple is at least trying to develop an Apple Watch with a blood pressure sensor built into the strap that will at least in part rely on a liquid-filled sensor.

The patent also indicates the sensor could be used independently of the Apple Watch, as well as in conjunction with an iPhone as you might expect.

As noted, given this patent has only just come to light, it seems unlikely this tech will appear in 2025's Apple Watch lineup and is more likely years away.0

If it ever does see the light of day, it could be a novel Apple solution to blood pressure monitoring. Indeed, it's a concept that has already been successfully deployed in the Huawei Watch D2.

The Apple Watch Ultra 3 and Series 11 should come with some sort of high blood pressure detection when they arrive later this year. However, this is likely to be a sensor that can pick up abnormal readings, rather than one that can deliver specific results, akin to sleep apnea detection on existing models.

Stephen Warwick is TechRadar's Fitness & Wearables writer with nearly a decade of experience covering technology, including five years as the News Editor of iMore. He's a keen fitness enthusiast and is never far from the local gym, Apple Watch at the ready, to record his latest workout. Stephen has experience writing about every facet of technology including products, services, hardware, and software. He's covered breaking news and developing stories regarding supply chains, patents and litigation, competition, politics and lobbying, the environment, and more. He's conducted interviews with industry experts in a range of fields including finance, litigation, security, and more. Outside of work, he's a massive tech and history buff with a passion for Rome Total War, reading, and music.