Apple has officially launched an updated “hypertension alerts” feature to Apple Watch users in India. The feature works by using the watch’s optical heart sensor to collect PPG (photoplethysmography) data over a 30-day period. And feeding that into a machine-learning algorithm that can detect signs of chronic high blood pressure — even if the user doesn’t yet know they have it.

It is important to note that The Apple Watch does not directly monitor blood pressure or display the actual BP values. Instead when the algorithm detects patterns that are consistent with hypertension. It sends you an alert that suggests you might be able to measure your blood pressure using the traditional cuff.

Alerts are targeted at those aged 22 or older who haven’t before diagnosed as having hypertension and who aren’t pregnant. It is currently available with Apple Watch Series 9, 10, 11, and models starting with Ultra 2 onwards.

In tests conducted on more than 2,200 adults, the device demonstrated ~41.2 percent sensitivities (catching certain people suffering from hypertension) and ~92.3 percent specificity (correctly identifying people without hypertension). It’s about the same as numerous BP-cuff measurements that are that are used in clinics.

According to Apple the fact that hypertension typically is not detected — possibly impacting more than one billion people around the world. This feature could assist in raising early warnings and help users check their BP correctly and speak with an expert, thus reducing the risk for heart attack, stroke, or kidney disease.