Apple told some of the participants in its joint heart study with Stanford (Calif.) University School of Medicine that it had completed collecting their data over the Labor Day weekend, according to the blog MacRumors.
The iPhone maker launched the study in collaboration with American Well and Stanford in November 2017. Customers of at least 22 years of age with an Apple Watch Series 1 or later were eligible to enroll in the study, which uses the Apple Watch's heart rate sensor to collect data on irregular heart rhythms known as atrial fibrillation. Enrollment to new participants closed Aug. 1.
As part of the study, participants were asked to download and install the Apple Heart Study app and regularly wear their Apple Watch. If the Apple Watch identified an irregular heart rhythm, the participant would be connected to a free virtual physician consultation facilitated by American Well.
Over the Labor Day weekend, some study enrollees received an app notification thanking them for their participation and asking them to complete an exit survey.
Apple previously said it planned to continue the study until Jan. 1, 2019, but according to MacRumors, the participants who received the notifications enrolled early, suggesting that data collection is slowing over stages.