Fitbit was one of the first tech companies to convince people that wearing a continuous heart rate sensor on your wrist was a good and useful thing to do. But in the years since releasing its first heart rate-tracking band, Fitbit has fallen behind when it comes to advanced health features. For instance, Apple put a medical-grade electrocardiogram sensor in its Apple Watch Series 4, which is able to detect atrial fibrillation with clearance from the U.S. Food and Drug Administration. That was back in 2018.
Fitbit just launched the Fitbit Heart Study with the goal of enrolling 250,000 people to prove that its algorithm can accurately detect atrial fibrillation. It will then take that data and submit it the the FDA. If Fitbit wins clearance, it will develop a feature for future devices that will passively monitor your heart rate and alert you to an irregular rhythm—a sign of atrial fibrillation, which is a disease that can lead to stroke or heart attack. Fitbit may also develop an ECG app similar to the one in the Apple Watch Series 4 and Series 5.
But first, it has to convince people to sign up for the study. Fitbit is aiming for users 65 and older, because they’re at higher risk for AFib.
While Apple was able to prove it could diagnose AFib without offering built-in sleep-tracking, Fitbit research scientist Tony Faranesh told Gizmodo that Fitbit’s continuous heart rate-tracking, which works even overnight while users are sleeping, gives the algorithm more data. That’s important, because atrial fibrillation is episodic—in other words, it’s not a consistently irregular heart rhythm, and episodes can happen every so often.
“You may have to look for a very long time to catch an episode,” Faranesh said. “Our goal is not just to notify the user, but also provide some historical data to facilitate the conversation with a physician.”
Fitbit users with heart rate-monitoring trackers or smartwatches who choose to opt into the study will have the previous 30 days of their heart rate data analyzed to start. If the algorithm detects atrial fibrillation, they’ll immediately see a notification in the Fitbit app on their smartphone. The alert will offer the option to talk with a telehealth physician, who will order an ECG monitor that the user will wear on their chest to monitor their heart. They’ll wear that patch with a Fitbit for a week, then send it back to the physician. After the results are analyzed, the physician will schedule a follow-up appointment to review the diagnosis and offer recommendations as to how to proceed.
“Finding out that you have heart disease can be traumatic,” Fitbit co-founder Eric Friedman, who is also the company’s chief technology officer, told Gizmodo. “Part of the reason we’re working with this telemedicine provider is to be able to get [users] a doctor’s appointment, potentially within minutes, but definitely within hours. They can understand it, talk them through it, give them advice on how to talk to a physician.”
Once the study concludes, Fitbit will submit its findings to the FDA for review. In terms of privacy, Fitbit is following the steps that other tech companies who conduct clinical studies (including Apple with its Apple Heart Study) have followed. Faranesh said the study has been reviewed by an ethics board and that all of the data collected is de-identified. Users who enroll will have to sign a HIPAA authorization to share their data with a physician if necessary as part of the study. The data will be archived following conclusion of the trial.
If the FDA concludes that Fitbit’s algorithm can accurately diagnose AFib, the company will start working on both a passive tracking system and an ECG app, similar to Apple’s, that could appear on the next generation of Fitbit’s trackers and smartwatches. This could potentially save lives—AFib contributes to some 130,000 deaths in the U.S. each year, and many people who have the disease never experience symptoms.
Fitbit is also working on FDA clearance for sleep apnea diagnosis, which would be a unique medical-grade feature in the smartwatch landscape. If Fitbit is cleared by the FDA to add diagnostic tools to its devices, it’s worth noting that the company is about to officially be under Google’s umbrella. Some users might be skeptical that life-saving features are worth handing Google so much of your personal health data—and they might be right.