Your Apple Watch may soon be able to save your life.

The devices used for everything from messaging friends to shopping may also be able to curb stroke risk by detecting atrial fibrillation — or irregular heartbeats — before they’re otherwise noticeable, according to Apple and Johnson & Johnson. 

The two companies announced Tuesday that they’re teaming up to study if the watch’s digital health tools can detect such irregularities. Open enrollment in the study, which is called Heartline, begins Tuesday and is open to people 65 and older who are covered by Medicare and own an iPhone 6 or later model.

The study may help “patients understand and directly engage in their heart health, prompting potentially life-saving conversations with their doctors,” Dr. Michael Gibson, co-chair of the Heartline executive committee and professor at Harvard Medical School, said in a statement.

Participants will be divided between two groups, one group with the Heartline app on their iPhone, and the other with the app on their iPhone and an Apple Watch with the ECG app and irregular rhythm notification feature. Participation in the study will last for three years with two years of active engagement, followed by an additional year of data collection. 

Participants selected in the Apple Watch group can either purchase a watch at a discount or can borrow one for free. Those who borrow will have to return the watch at the end of the study.

People with AFib often don’t show symptoms and end up not getting treated. Between 2.7 million and 6.1 million people in the U.S. have AFib, and the number is expected to increase as the population ages, according to the Centers for Disease Control and Prevention. The condition increases the risk of stroke.

“Apple technology is making a meaningful impact on scientific research through the powerful capabilities of iPhone and Apple Watch, all with privacy at the center of the participant experience,” Myoung Cha, Apple’s Head of Health Strategic Initiatives, said in a statement. “The Heartline Study will help further understanding of how our technology could both contribute to science and help improve health outcomes, including reducing the risk of stroke.”

  • Previous research published in November in the New England Journal of Medicine showed that about 0.5% of the more than 400,000 participants in the Apple Heart Study received an irregular heart notification, Stanford researchers reported. Some members of the medical community weren’t convinced that the Apple Watch was the right tool for notification, CNBC reported.
  • The European Union is reviewing Google’s plan to buy Fitbit Inc. The EU antitrust chief said privacy regulators won’t be involved in the approval process after watchdogs raised concerns about how tech giants could use people’s private information.