A major new health feature for recent Apple Watch models can alert users to possible hypertension (aka high blood pressure) by analyzing patterns in their heart data over time. Apple offered a document earlier this week explaining how the Hypertension Notifications feature works using existing sensors.
Available with watchOS 26, the feature works on Apple Watch Series 9 and later models, as well as the Apple Watch Ultra 2 and later.
Hypertension Notifications: How the technology works
Unlike rumored blood pressure monitoring capabilities that would require new hardware, Apple’s hypertension detection comes in watchOS 26 and uses existing optical heart sensor already built into recent Apple Watches. The company developed a new algorithm that analyzes heart data collected over extended periods to identify patterns associated with chronic high blood pressure. And the feature has received FDA approval, lending credibility to Apple’s approach.
The feature requires 30 days of data collection before it can provide notifications. The evaluation period begins from the moment users set up hypertension notifications through the Health app on their iPhone. If the system identifies patterns related to hypertension within the last 30 days of collected heart data, users will receive a notification on their watch.
Apple noted the technology looks for physical changes in veins and arteries over time, rather than providing real-time blood pressure measurements. The company has been clear that it’s not the same as blood pressure monitoring, which remains technically challenging to implement on wearable devices.
Who can use the feature
Hypertension alerts are designed for a specific user group. Apple requires users to be 22 years or older, not pregnant and have no previous diagnosis of hypertension. The feature must be manually enabled (not available by default), likely due to these specific eligibility requirements.
To activate the feature, users need an iPhone 11 or later running the latest iOS, paired with a compatible Apple Watch running the latest watchOS. Wrist Detection must also be enabled for the feature to function properly. The Hypertension Notifications feature is not available on Apple Watch SE models.
What happens after receiving an alert
The notification serves as a prompt for medical consultation rather than a definitive diagnosis. When users receive a hypertension notification, Apple strongly encourages them to discuss the alert with healthcare professionals.
Users who receive alerts get prompts to set up a Blood Pressure Log and use a third-party blood pressure cuff to measure and track their blood pressure for seven days. The log includes options for recording date, time, and systolic and diastolic pressure readings, with daily reminders for morning and evening measurements.
Important limitations and disclaimers
Apple also made clear what the feature cannot do. Hypertension Notifications aren’t intended to diagnose, treat or manage hypertension or related conditions such as blood clots, stroke, atrial fibrillation, congestive heart failure or high cholesterol.
The company also warns that not all people with hypertension will receive notifications, and the Apple Watch cannot detect heart attacks. Users experiencing chest pain or symptoms of a heart attack should immediately contact emergency services rather than relying on their device.
David Snow, an expert on Apple hardware and software, writes on a variety of technological and cultural topics for Cult of Mac. They include Apple news, technology buying guides, and features about computer setups and Apple TV shows and movies.
With 30 years of experience covering technology and other subjects, he has written and edited for numerous print and online publications, including CMP Media, TechTV.com, CNET, Wired News, Red Herring magazine, Law.com, The National Law Journal and Law Technology News magazine. Among other roles, he served as executive editor of the Law.com network of websites and editorial director, technology, for ALM Media.
Snow graduated with a B.A. from Syracuse University with majors in magazine journalism and psychology. While there, he worked as a reporter for The Daily Orange newspaper and associate editor of Equal Time magazine.
Founder of the blog At the Waterline, he can be reached on X (formerly Twitter) via @atthewaterline and on Mastodon via @dsnow.
