Apple on Wednesday activated its hypertension notification feature for Apple Watch users in India, months after first announcing the capability alongside the iPhone 17 and new Watch Series in September. The rollout adds one of the company's most significant health tools to date in a country with a rapidly expanding base of smartwatch users and a high burden of undiagnosed hypertension.
The feature uses the Watch's optical heart sensor to passively analyse blood vessel response patterns over a 30-day period. If the algorithm detects consistent signs linked to chronic high blood pressure, users receive a notification prompting further medical evaluation. Apple says the feature is expected to surface early warning signs in more than one million people globally in its first year of use.
Hypertension remains one of the most common yet frequently undiagnosed conditions worldwide, largely because it shows no symptoms and often goes unnoticed during routine medical visits. India, which now has one of the world's largest young and middle-aged smartwatch populations, represents a substantial pool of users who could benefit from passive detection.
The notification algorithm is backed by machine learning models trained on data from more than 100,000 participants, and its performance was validated in a clinical study involving over 2,000 individuals. However, Apple cautions that the feature cannot detect all instances of high blood pressure and is not intended for users under 22, pregnant individuals, or those already diagnosed with hypertension.
"Integrating opportunistic detection into a device people already wear daily will democratise access for early detection and help people have more informed conversations with their doctors," said Professor Dorairaj Prabhakaran of the Centre for Chronic Disease Control and president-elect of the World Heart Federation.
Users who receive an alert are advised to log their blood pressure for seven days using a certified blood pressure monitor before consulting their healthcare provider—reflecting the current American Heart Association guidelines.
The feature is supported on Apple Watch Series 9 and later, as well as Apple Watch Ultra 2 and newer models, and is available through a software update.
