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A man looks at his heart rate on a smartwatch

Can Smartwatches Detect AFib Accurately?

Posted in: Blogs , English

From playing music to receiving calls and texts, it seems like your smartwatch can do anything nowadays. Apple is trying to take it a step further with claims that the Apple Watch can detect the signs of atrial fibrillation, but is this tech something you can trust? 

What Is Atrial Fibrillation? 

Atrial fibrillation, also known as AFib, is an irregular heartbeat that, without treatment, increases your risk of stroke. It occurs when the electrical signals that tell your heart when to contract don’t work as they should. Some people with AFib have no noticeable symptoms, while others may experience a fluttering or rapid heartbeat, fatigue, dizziness, or weakness. 

How Can a Smartwatch Detect Atrial Fibrillation? 

Researchers at Stanford recently conducted a study on the ability of the first three series of Apple Watches to detect AFib. The watches included in the study used a light sensor to measure blood flow at different times. If the sensor repeatedly detected irregular flow, it would send an alert.

Of the over 400,000 people who participated, only 0.5% received a notification that they might have the condition. Of the 54% of people who followed up the alert with a doctor’s appointment, around 70% displayed signs of AFib after wearing an ECG patch for one week to monitor heart rhythm. 

What Are the Risks of Relying on a Smartwatch to Detect AFib? 

Two main risks come with relying on wearables to notify you of potential health conditions. The first is false positives. People might spend time and money on chasing down an answer only to find it was a false alert. On the other hand, if you’re relying on the wearable to diagnose a condition and you never get an alert for it, you probably won’t seek a healthcare provider’s opinion. These watches have the potential to provide a false sense of security if they don’t pick up on the signs of an existing condition.

While you shouldn’t replace regular doctor’s appointments with a smartwatch, these devices can help you be more aware of your general health. If you notice unusual symptoms or find yourself feeling faint, dizzy, or tired, schedule an appointment with a St. Luke’s Health cardiologist or primary care physician. Our team will work to find treatments and solutions tailored to you. 


NCBI | Rationale and design of a large-scale, app-based study to identify cardiac arrhythmias using a smartwatch: The Apple Heart Study.
AJMC | Giant Study Suggests Apple Watch Accurately Catches Atrial Fibrillation
Business Insider | Stanford scientists just gave us an unprecedented look at how well the Apple Watch detects heart problems
ABC News | Apple Watch can help doctors diagnose atrial fibrillation

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