Among the many diseases that can be present in the body without a person even knowing about it, high blood pressure is arguably the most common. There is an estimate that it affects more than 1.4 billion people worldwide and about 40 percent of them do not even know they have it. To deal with this problem, Apple added a new hypertension notification feature to the Watch a few months ago. Watch Series 9 and newer and Apple Watch Ultra 2 and newer are supported. Now, after regulatory approval, the feature is rolling out in India.

Apple says the Hypertension Notification feature will alert users if chronic high blood pressure or symptoms of hypertension are detected. This is a one-time alert feature. It uses specific algorithms to monitor data collected through the optical heart sensor on the Apple Watch. This data is analyzed to see how the user’s blood vessels respond to the heartbeat and after the analysis lasting 30 days, the Watch will notify users if it detects persistent symptoms of high blood pressure.

Adam Phillips, cardiologist at Apple, told India Today Tech, “As a physician in cardiology, this is something we often see where people suffer from high blood pressure for years and don’t know it because it’s an asymptomatic disease.” “So having this feature available to our users at the scale that Apple operates at is really huge.”

Philips says that this feature has been developed with great care and thoroughness and false positives have been greatly reduced. “We developed our feature with great rigor both in the development phase and the clinical validation phase, and we developed (high blood pressure notification) with over a lakh participants in development and then clinically validated it with over 2000 participants,” he says. “We expect to notify more than one million people in the first year alone.”

The feature could prove especially useful for Watch users in India, a country where high blood pressure is almost endemic, with the report saying that one in every three Indians is likely to have high blood pressure. And yet, the prognosis of the disease remains poor because symptoms are rarely visible in the early stages.

alert but not blood pressure monitoring

As this feature is rolling out, it’s important to understand what it does and doesn’t do. It is quite simple. This feature, as its name suggests – Hypertension Notification – is a one-time alert that can help Watch users detect a condition they may not be aware of. To do this, as mentioned earlier, the Watch relies on data collected through a heart rate sensor. In that sense, this feature does not perform on-demand blood pressure recording like machines with cuffs do.

To enable the feature, users will have to set it in the Health app. During the setup process they will be asked to fill in some details like age. Only users 22 years of age or older can use this feature. Also if you already have high blood pressure and you take medicines for it, then High Blood Pressure Notification is not for you.

Once it detects latent hypertension, the Watch will encourage users to undergo intensive testing. Phillips says that once the Watch detects high blood pressure, “it will give (users) next steps that are actually actionable, so they can check their blood pressure using a regular blood pressure machine (and) log it at home”.