RELATED: Doing This Raises Your Stroke Risk 60 Percent Within an Hour, New Study Finds. Age is certainly a risk factor for stroke, but did you know that the risk is five times higher for people who regularly experience an irregular heartbeat—known as atrial fibrillation (AFib)? According to a blog post published by Fitbit, that’s where their device comes in. This wearable smartwatch is used to monitor your physical activity, daily steps, and quality of sleep. However, the Food and Drug Administration (FDA)  recently cleared a new photoplethysmography (PPG) algorithm to check for AFib. If it detects signs of this condition, your Fitbit will let you know via an “Irregular Heart Rhythm” notification.ae0fcc31ae342fd3a1346ebb1f342fcb Approximately 37.5 million people are living with AFib across the world, according to a 2021 study published in the International Journal of Stroke. That’s a 33 percent increase from 20 years ago. Despite this staggering number, AFib is challenging to diagnose, as it often has no symptoms and episodes can be sporadic, according to a separate study published in the New England Journal of Medicine. Fitbit controls for this with its background AFib monitoring. According to a May 2020 press release from Fitbit, this feature is particularly useful at night, when you’re asleep. “The optimal way to identify irregular rhythm through heart rate tracking technology is to screen when the body is at rest, making assessment overnight, while people sleep, ideal for detection,” the company stated. RELATED: For more up-to-date information, sign up for our daily newsletter. The passive heart monitoring feature was evaluated in the 2020 Fitbit Heart Study, which enrolled 455,699 participants (none of whom self-reported a prior AFib diagnosis). Participants were instructed to wear a Fitbit, which collected data to be analyzed by the then-novel algorithm. If an irregular heartbeat was detected, participants met with a telehealth professional, then wore an electrocardiogram (EKG) patch with their Fitbit for another week. Study findings were presented at the 2021 American Heart Association (AHA) Scientific Sessions, where the authors said the data suggested that Fitbit’s technology identified AFib episodes 98 percent of the time (as confirmed by the EKG patch). “These results show that wearables have the ability to identify undiagnosed atrial fibrillation with high reliability,” principal study investigator Steven A. Lubitz, M.D., M.P.H., associate professor of medicine at Harvard Medical School and cardiologist at the Massachusetts General Hospital in Boston, said in the AHA press release that outlined the study findings. “Since so many consumers use wearables, it is possible that algorithms such as the one we studied could be applied widely to help identify undiagnosed atrial fibrillation, allowing patients to obtain care before devastating complications such as a disabling stroke may occur.” According to Fitbit’s blog post, the new feature will soon be available in the U.S. And The Verge reports that Fitbit owners can already spot-check for AFib with a manual EKG app—a feature cleared by the FDA in 2020. While these devices can’t diagnose AFib, if something is amiss, users can review long-term heart rhythm assessments with a doctor, potentially resulting in an early diagnosis. Experts suggest this could then reduce the risk of more serious conditions. “Undiagnosed atrial fibrillation can lead to strokes, and early detection of atrial fibrillation may allow doctors to prescribe medications that are effective at preventing strokes,” Lubitz said. Fitbit’s 2020 study did not directly evaluate whether or not AFib screening directly leads to a reduction in strokes, the AHA press release said. According to Lubitz, this specific relationship is an area that will need to be further investigated by experts. RELATED: 80 Percent of Strokes Could Be Prevented by Doing These 4 Things, CDC Says.