Your Fitbit just got one of the Apple Watch’s key features

Fitbit Versa 3 review
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One of the features on the Apple Watch that makes it the best smartwatch is its ability to look for irregular heart rhythms as you wear the watch. But Apple's device is about to get some competition in that regard.

Fitbit has received approval from the U.S. Food and Drug Administration for an algorithm that can detect atrial fibrillation (AFib) and send Fitbit wearers alerts about what it has detected. The new capability augments the ECG feature found on some of the best Fitbits that lets you proactively scan for AFib.

The newly approved algorithm is an important addition because it works in the background. That allows users to record data over time that can help with early detection of heart issues.

Google, Fitbit's parent company, has a detailed explanation of how the photoplethysmography, or PPG, algorithm can detect AFib, but essentially, it's able to detect changes in blood volume from the sensors on your Fitbit wearable. Using these measurements, the algorithm is able to detect any irregularities.

Since this is passive detection, the scans happen as you're at rest or asleep. That's especially beneficial to Fitbit, which touts long battery life among its many features. In other words, the longer you wear your Fitbit — particularly overnight — the more detailed reading the PPG algorithm is going to be able to detect.

The feature described by Google is not dissimilar to what the Apple Watch does. Since the Apple Watch 4 came out, Apple's wearable has offered a feature that's can send you alerts if it detects a number of irregular heartbeats over time. 

Atrial fibrillation is certainly a problem — Google says AFib affects nearly 33.5 million people worldwide, putting anyone with AFib at a higher risk of stroke. Neither the Apple Watch nor Fitbit devices can diagnose AFib, but they can collect enough data to present to a doctor to assess potential problems, particularly in the early stages. That's why medical professionals recommend enabling heart rate notifications on devices that support such a feature.

Which Fitbits will Atrial fibrillation be available on? 

The update, rolling out in the US now, is available on the following trackers: Fitbit Charge 3, Fitbit Charge 4, Fitbit Charge 5, Fitbit Inspire 2, Fitbit Luxe, Fitbit Sense, Fitbit Versa 2, Fitbit Versa 3, Fitbit Versa Lite. 

Philip Michaels

Philip Michaels is a Managing Editor at Tom's Guide. He's been covering personal technology since 1999 and was in the building when Steve Jobs showed off the iPhone for the first time. He's been evaluating smartphones since that first iPhone debuted in 2007, and he's been following phone carriers and smartphone plans since 2015. He has strong opinions about Apple, the Oakland Athletics, old movies and proper butchery techniques. Follow him at @PhilipMichaels.