Apple Closes Apple Watch Heart Rate Study to New Participants

Apple and Stanford University's School of Medicine are no longer allowing new participants to join the joint heart rate study that they're conducting using data gathered from the heart rate monitor of the Apple Watch, according to an updated notice on the Apple Heart Study website.

As of August 1, 2018, an enrollment termination date Apple and Stanford first announced when the study launched, enrollment is officially closed. While enrollment has ended, the study does not end until January 31, 2019, and Apple plans to continue collecting data from current participants until the completion of the study.

apple heart study

Note: Enrollment for this study is closed to new participants as of August 1, 2018. If you are currently enrolled, your participation will continue until the end of the study.

The Apple Heart Study is designed to use data from the Apple Watch to identify irregular heart rhythms to determine whether the wrist-worn device can accurately detect life-threatening conditions like atrial fibrillation.

The study was previously open to anyone in the United States who was 22 years older with an iPhone 5s or later and an Apple Watch Series 1 or later.

Participants were instructed to download and install the Apple Heart Study app and wear the Apple Watch. When an irregular heart beat is detected in a study participant, a consultation with a Study Telehealth provider from American Well is offered, with some people asked to wear an ePatch monitor for up to seven days for further investigation.

One MacRumors reader shared his story using the Heart Rate Study app and the accompanying patch after an abnormal rhythm was detected:

I believe that many of you don't understand just how much effort and expense Apple has spent on developing this research program. I signed up late last year, and several weeks ago they notified me that they had read an irregular heart rhythm on my app.

I called them, talked to a Dr. on line, they sent me a state of the art medical monitor the size of an Apple watch which is applied with a sticky tape over my heart for 7 days, I kept it attached for a week, sent it back (post payed) and they contacted me within 3 days, they had me contact one of their research Drs. who went over the results of the week long monitor, they saw no further arrhythmia, and gave me confidence that the earlier abnormal pattern was not a problem, readings showed my heart strong, and healthy.

With the study now closed to new participants, the Apple Heart Study app has been removed from the App Store. Apple has also removed its dedicated Apple Heart Study webpage from its site.

Apple's Heart Rate Study in collaboration with Stanford Medicine first launched in November 2017. Atrial fibrillation, a common form of heart arrhythmia that is covered in the study, can indicate serious medical conditions like heart failure and stroke. Afib affects millions of people but often goes undiagnosed, with the study aiming to determine if the Apple Watch is able to alert people of this dangerous condition and accompanying health problems.

Other studies conducted by the team behind the Cardiogram app and researchers at the University of California, San Francisco have suggested that the Apple Watch is able to detect an abnormal heart rhythm with 97 percent accuracy. It may also be useful in detecting early signs of other diseases like diabetes, hypertension, and sleep apnea.

applewatchheartrate
Currently, the heart rate monitor built into the Apple Watch (Series 1 models and later) will send an alert if a faster-than-normal resting heart rate is detected, a feature that has saved multiple lives. This heart rate monitoring option can be activated by opening up the Apple Watch app on the iPhone, selecting the heart rate app, and setting your high heart rate notification to the desired level.

appleheartratemonitor
While the Apple Watch sends alerts for a high heart rate, it does not notify people of abnormal rhythms or other issues that have been detected, but that could change in the future depending on the outcome of the study.

Rumors have suggested that 2018 Apple Watch Series 4 models will include enhanced heart rate detection features that could bolster the Apple Watch's ability to detect diseases linked to higher heart rates and abnormal heart rhythms, but it is not entirely clear what the enhanced heart rate features consist of.

New Apple Watch models, which are expected in September alongside the 2018 iPhones, are also said to include a new design with a 15 percent larger display.

Related Roundup: Apple Watch 11
Buyer's Guide: Apple Watch (Buy Now)

Popular Stories

iOS 26

When Will Apple Release iOS 26.2?

Monday December 1, 2025 4:37 pm PST by
We're getting closer to the launch of the final major iOS update of the year, with Apple set to release iOS 26.2 in December. We've had three betas so far and are expecting a fourth beta or a release candidate this week, so a launch could follow as soon as next week. Past Launch Dates Apple's past iOS x.2 updates from the last few years have all happened right around the middle of the...
ios 18 to ios 26 upgrade

Apple Pushes iPhone Users Still on iOS 18 to Upgrade to iOS 26

Tuesday December 2, 2025 11:09 am PST by
Apple is encouraging iPhone users who are still running iOS 18 to upgrade to iOS 26 by making the iOS 26 software upgrade option more prominent. Since iOS 26 launched in September, it has been displayed as an optional upgrade at the bottom of the Software Update interface in the Settings app. iOS 18 has been the default operating system option, and users running iOS 18 have seen iOS 18...
maxresdefault

iPhone Fold: Launch, Pricing, and What to Expect From Apple's Foldable

Monday December 1, 2025 3:00 am PST by
Apple is expected to launch a new foldable iPhone next year, based on multiple rumors and credible sources. The long-awaited device has been rumored for years now, but signs increasingly suggest that 2026 could indeed be the year that Apple releases its first foldable device. Subscribe to the MacRumors YouTube channel for more videos. Below, we've collated an updated set of key details that ...
iOS 26

Apple Seeds iOS 26.2 and iPadOS 26.2 Release Candidates to Developers and Public Beta Testers

Wednesday December 3, 2025 10:33 am PST by
Apple today seeded the release candidate versions of upcoming iOS 26.2 and iPadOS 26.2 updates to developers and public beta testers, with the software coming two weeks after Apple seeded the third betas. The release candidates represent the final versions of iOS 26.2 and iPadOS 26.2 that will be provided to the public if no further bugs are found during this final week of testing....
iphone 17 cyber

iPhone 17 Demand Is Breaking Apple's Sales Records

Tuesday December 2, 2025 9:44 am PST by
Apple's iPhone 17 lineup is selling well enough that Apple is on track to ship more than 247.4 million total iPhones in 2025, according to a new report from IDC. Total 2025 shipments are forecast to grow 6.1 percent year over year due to iPhone 17 demand and increased sales in China, a major market for Apple. Overall worldwide smartphone shipments across Android and iOS are forecast to...
Photos App Icon Liquid Glass

John Gruber Shares Scathing Commentary About Apple's Departing Software Design Chief

Thursday December 4, 2025 9:30 am PST by
In a statement shared with Bloomberg on Wednesday, Apple confirmed that its software design chief Alan Dye will be leaving. Apple said Dye will be succeeded by Stephen Lemay, who has been a software designer at the company since 1999. Meta CEO Mark Zuckerberg announced that Dye will lead a new creative studio within the company's AR/VR division Reality Labs. On his blog Daring Fireball,...
Touchscreen MacBook Feature

Here Are the Four MacBooks Apple Is Expected to Launch Next Year

Monday December 1, 2025 5:00 am PST by
2026 could be a bumper year for Apple's Mac lineup, with the company expected to announce as many as four separate MacBook launches. Rumors suggest Apple will court both ends of the consumer spectrum, with more affordable options for students and feature-rich premium lines for users that seek the highest specifications from a laptop. Below is a breakdown of what we're expecting over the next ...
iphone air camera

iPhone Air's Resale Value Has Dropped Dramatically, Data Shows

Thursday December 4, 2025 5:27 am PST by
The iPhone Air has recorded the steepest early resale value drop of any iPhone model in years, with new data showing that several configurations have lost almost 50% of their value within ten weeks of launch. According to a ten-week analysis published by SellCell, Apple's latest lineup is showing a pronounced split in resale performance between the iPhone 17 models and the iPhone Air....
iPhone 17 Pro Cosmic Orange

iPhone 17 Pro Lost a Camera Feature Pro Models Have Had Since 2020

Thursday December 4, 2025 5:18 am PST by
iPhone 17 Pro models, it turns out, can't take photos in Night mode when Portrait mode is selected in the Camera app – a capability that's been available on Apple's Pro devices since the iPhone 12 Pro in 2020. If you're an iPhone 17 Pro or iPhone 17 Pro Max owner, try it for yourself: Open the Camera app with Photo selected in the carousel, then cover the rear lenses with your hand to...
chatgpt logo

Sam Altman Declares 'Code Red' for ChatGPT, Delays OpenAI Advertising Plans

Tuesday December 2, 2025 3:30 pm PST by
OpenAI is deprioritizing work on advertising as it focuses on improving the quality of ChatGPT, reports The Information. OpenAI CEO Sam Altman declared a "code red" on Monday, and told employees that the company needs to improve ChatGPT so it doesn't fall behind competitors like Google and Anthropic. Altman said that OpenAI needs to work on personalization for each user, image generation,...

Top Rated Comments

BigMcGuire Avatar
96 months ago
Cool! My wife and I participate.

Attachment Image
Score: 7 Votes (Like | Disagree)
Robin4 Avatar
95 months ago
I did not know about the study. I did not understand how the heart rate could help me. I was interested in exercise, breathing, etc.

Last Sunday I clearly understood how the heart rate info would help me. Sat. and Sunday I felt tired after walking the dog a short time. I was jittery and tired. I went to bed and started reading.
2 hours later I get a message from my Apple Watch. It read something like this. “You have been resting for a while but your heart rate reads “41”. It might be advisable to get in touch with your doctor.”

Just in case I tried calling the doctor. Of course being Sunday, I talked to the nurse. She asked me a few questions and advised me to go to the hospital. she called EMS. As we were talking firemen and an ambulance showed up. I found myself surrounded by doctors asking if I had a will, a living will, etc. After getting scans, etc. Etc, they told me that the top part of my heart was hardly communicating with the bottom half.
They had an emergency operation, inserted a pacer. The doctors were shocked to hear my Apple Watch warned me of trouble. After telling my story to so many people in the hospital, I thought I would thank Tim Cook. A few hours later I received a reply wishing me well.

I’m still amazed how life is so fragile.
Score: 4 Votes (Like | Disagree)
JackieInCo Avatar
96 months ago
It’s frustrating that when you restore your phone you lose this. It should only need to reconnect you to your existing study. Instead it thinks you’re an entire new request. And now that it’s closed doors. SoL.
I have the study going on three different iPhones. I managed this by restoring my 6S+ backup onto my 7+ and 8+. Now, no matter what phone I use to pair my watches with, it continues the study on that phone. Since my backup restored everything identical to the 6S+ the Apple study app uses the same email address so the number of contributions stay the same on all three phones. I have 6 watches so there are times I have a watch paired to all three phones.

My backups are encrypted so maybe that is why I was able to restore the Apple study to all the phones. Screencap shows my 7+ and 8+ with the app showing the current stats and start date. The stats are just a bit different because I wore the watch with my 8+ today so they haven't quite synced up yet to show the same stats.



Attachment Image
Score: 4 Votes (Like | Disagree)
mmcneil Avatar
96 months ago
Just had an appt with my cardiologist and was showing her the apps. It was all new to her. It would great if they publish in the medical journals and get wider interest and acceptance. I am participating in both studies. Looking forward to Series 4, didn’t think the Apple Watch would be something I upgraded regularly lol
Score: 4 Votes (Like | Disagree)
DocMultimedia Avatar
96 months ago
I'm glad to help out in big studies like this (600 contributions so far). I do everything from marathons to one milers (55 yrs old), so I'm sure my heart data is a nice addition. Hopefully healthy!

No phone calls yet. Fingers crossed.
Score: 3 Votes (Like | Disagree)
centauratlas Avatar
96 months ago
I hope they do a phase 2 or something, perhaps with the potentially improved monitor on the next one.
Score: 3 Votes (Like | Disagree)