Apple Watches will soon monitor how well blood vessels in the wrist respond to their owner’s beating heart, and warn them if they’re showing signs of hypertension, Apple said.

Launching new models of the Watch, as well as new AirPods earphones that can track their owner’s heart rate without the need for a Watch, Apple said the novel technique for detecting hypertension could warn a million people a year that they’re at risk of a heart attack.