Apple's Heart Study app can identify irregular heart rhythms

The app uses Apple Watch's sensor to calculate heart rate and rhythm, and can notify users who might be experiencing atrial fibrillation.

Abrar Al-Heeti Technology Reporter
Abrar Al-Heeti is a technology reporter for CNET, with an interest in phones, streaming, internet trends, entertainment, pop culture and digital accessibility. She's also worked for CNET's video, culture and news teams. She graduated with bachelor's and master's degrees in journalism from the University of Illinois at Urbana-Champaign. Though Illinois is home, she now loves San Francisco -- steep inclines and all.
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2 min read

Your Apple Watch can now tell you if you have an irregular heart rhythm.

Apple launched its Heart Study app on Thursday, which uses the Apple Watch's heart rate sensor to collect data on a wearer's heart rhythms and then notify them if they might be experiencing atrial fibrillation, or AFib.


Using the Apple Watch, the Heart Study app can notify users if they have irregular heart rhythms. 


This technology could be important for detecting a condition that doesn't always show symptoms. In the US, approximately 750,000 hospitalizations and 130,000 yearly deaths are a result of AFib, according to the Centers for Disease Control and Prevention.

The Watch's sensor calculates heart rate and rhythm using green LED lights that flash hundreds of times per second. Light-sensitive photodiodes detect how much blood is flowing through the wrist. The sensor then collects signals from four points on the wrist, and, combined with software algorithms, the Watch can isolate heart rhythms from other "noise." Using this method, the Apple Heart Study app can identify an irregular heart rhythm.

Apple is partnering with Stanford Medicine to conduct the research.

"Working alongside the medical community, not only can we inform people of certain health conditions, we also hope to advance discoveries in heart science," said Jeff Williams, Apple's COO, in a statement.

If an irregular rhythm is detected with the Hearth Study app, a person gets a notification on their Apple Watch and their iPhone , as well as a free consultation with one of the study's doctors and an ECG patch so they can be further monitored.

Previously, Apple Watch users could add products like the FDA-approved Kardia Band to their device to provide EKG readings and possibly detect heart conditions like AFib. Now, the watch can do this on its own.

Apple has increasingly been bringing tech and medicine together. Its ResearchKit software framework, launched in 2015, was designed for researchers to conduct studies through available apps. CareKit, another open source framework that launched last year, lets people develop health apps. ResearchKit and CareKit have been used by more than 500 researchers and over 3 million participants, according to Apple.

The Heart Study app is available in the US via Apple's app store for people age 22 and up, and who have an Apple Watch Series 1 or later. 

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