Unless you're keeping tabs on your heart rate at all hours of the day, it can be near impossible to pinpoint an irregular heartbeat.
But with more people strapping on fitness trackers and smartwatches, crucial data about patient heart rates could be hiding within those connected wristbands, tracing every move. Could those smartwatch sensors really be accurate enough to help stop a stroke?
One research team is trying to find out.
Heart researchers from the University of California, San Francisco as well as developers behind the heart rate-tracking app Cardiogram are teaming up to investigate if the tech built into smartwatches could be used to identify those at risk for a stroke or heart failure.
The research team will be honing in on one of the most commonly undiagnosed irregular heart conditions: atrial fibrillation, an irregular and often rapid heart rate also known as a type of arrhythmia.
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Working within an observational study dubbed mRhythm, which kicked off on Wednesday, researchers will track data from participants using both the Apple Watch and Android Wear-based devices while looking for signs of irregular heart rates. These kinds of watches don't have advanced electrocardiogram (EKG) machines inside. But they do include cheaper technology, such as LED lights, which can be used to measure blood flow in the wrist.
Still, out-of-the-box smartwatches and apps are not always reliable when it comes to health tracking yet.
Top-selling AuraLife's Instant Blood Pressure app was recently reprimanded for giving inaccurate results most of the time, telling users that their blood pressure levels were within the normal range when in fact they were elevated.
But so far, fitness trackers have largely skirted any regulation by the FDA.
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In the hopes of offering a more accurate system on the Cardiogram app, the new study will also enroll some patients who have already been diagnosed with atrial fibrillation. Those patients, who already use more high-tech monitors, will help in teaching the software as to what an irregular heart rates look like and what could make the tool better at diagnosing symptoms.
Dr. Greg Marcus, who is leading the study at UCSF, notes that if doctors can find more at-risk patients early on, they can prescribe preventative medication to reduce the chances of a stroke.
But as Dr. Marcus himself says of the smartwatch tracking, "the first step is to prove that it works."