This week, Hypertension notifications became available on the Apple Watch in Australia. It works on Apple Watch Series 9 and later, and Apple Watch Ultra 2 and later. The feature alerts users if signs of chronic high blood pressure or hypertension are detected.
Hypertension is the leading modifiable risk factor for heart attack, stroke, and kidney disease, and impacts approximately 1.4 billion adults globally. It is frequently undiagnosed because it often has no symptoms, many people do not see a doctor regularly, and even during a clinical visit, it can be easily missed with a single measurement.
How It Works
The Apple Watch does not measure blood pressure. This is important to note.
Hypertension notifications on Apple Watch use data from the optical heart sensor to analyse how a user’s blood vessels respond to the beats of the heart. The algorithm works passively in the background, reviewing data over 30-day periods, and will notify users if it detects consistent signs of hypertension.
So essentially, Apple is using the hardware already built into the Apple Watch, but it’s the clever algorithm that makes the assessment over time that the wearer may have an issue with high blood pressure.
“Hypertension awareness in Australia is far too low, so we welcome new technologies that advise people that they might have hypertension and should seek confirmation from their doctor,” said Professor Garry Jennings, chief medical advisor at the Australian Heart Foundation.
“Despite high blood pressure causing a greater risk of heart attack and stroke, only about a third of adults with hypertension are aware of it and have their blood pressure lowered to satisfactory levels.”
Hypertension notifications are not intended for use by people under 22 years old, those who have been previously diagnosed with hypertension, or if pregnant.
Validation
The feature was developed with advanced machine learning and training data from over 100,000 participants. Its performance was then validated in a clinical study of over 2,000 participants. While hypertension notifications will not detect all instances of hypertension, with the reach of Apple Watch, it’s estimated the feature will notify over one million people with undiagnosed hypertension worldwide within its first year of availability.
What Happens When a Notification is Received?
If users receive a hypertension notification, it is recommended that they log their blood pressure for seven days using a third-party blood pressure cuff and share the results with their provider at their next visit, which is consistent with the latest guidelines for the diagnosis and management of hypertension.
