(Pocket-lint) - Apple has launched a new app.

It isn't a productivity app or video app or note-taking app or any of that usual app stuff. Instead, this new app will allow the company to collect your heart rhythm data, as long as you're wearing the Apple Watch. Called the Apple Heart Study app, it uses the watch's heart rate sensor to detect irregularities. It can measure hear rate through green LED lights that flash hundreds of times per second.

With photodiodes, the app can analyse the amount of blood flowing through your wrist, and if it notices you may be suffering from atrial fibrillation, it'll send you a notification. Users who participate will be notified on their iPhone and Watch and provided a free consultation with a study doctor and an electrocardiogram (EKG) patch. But you have to be 22 years or older and have an Apple Watch Series 1 or later.

Apple also plans to use this data to help researchers advance discoveries in heart science and cases of heart irregularity. Apple first revealed it was working toward this initiative, in partnership with Stanford University, when it released WatchOS 4 in September. But the launch of Apple's Heart Rate Study app happens to coincide with news about the first US Food and Drug Administration-cleared EKG reader for Apple Watch.

Called the AliveCor's KardiaBand electrocardiogram (EKG) reader, it's a medical device accessory, or sensor, for the Apple Watch. It pairs with an app and can detect abnormal heart rhythm and atrial fibrillation, as well. KardiaBand is available now for $199, and requires a subscription to AliveCor's premium service, which costs $99 a year. You can learn more about how it works in the video below.

Apple's Heart Study app is currently available in the US App Store.

Writing by Elyse Betters.