Wearables such as Fitbit, Apple Watch, and other fitness devices that can potentially lead to better health are ubiquitous these days. The ability to monitor weight, sleep function, steps taken, calories burned, and more has motivated many people to get and stay healthy. But what if our fitness trackers could measure more serious health challenges, and possibly even save lives? A recent study presented at the American Heart Association found that some wearables can accurately detect serious conditions like hypertension (high blood pressure) and sleep apnea.

The study from health startup Cardiogram and the University of California San Francisco (UCSF) suggests that wearables like Fitbit and Apple Watch were able to accurately detect and monitor hypertension and sleep apnea, which often go undiagnosed. 6,115 subjects participated in the study using the Cardiogram app to test their Apple Watch. The study discovered that 1,016 of the participants suffered from sleep apnea, while 2,230 had hypertension. This was done using a machine learning algorithm called DeepHeart. According to a recent TechCrunch article, DeepHeart was trained on data from 70 percent of participants, both those with sleep apnea and hypertension and those without, then tested on the remaining 30 percent of participants. The study demonstrated that data from an Apple Watch can be used to detect sleep apnea with 90 percent accuracy and hypertension with 82 percent accuracy. Researchers concluded that this level of accuracy was high enough for an initial screening for the conditions; a standard doctor’s visit would be required to confirm the diagnosis. The Cardiogram app was originally developed for Apple Watch, but can now be used with other wearables including Fitbits, Garmins, and Android Wear devices. Sleep apnea is a condition in which breathing stops and starts throughout the night; it affects an estimated 22 million adults in the U.S. and can be fatal. Around 75 million American adults have hypertension, which puts them at risk for heart disease, stroke, and kidney disease.

Because hypertension and sleep apnea often go undiagnosed, this new use of common wearable devices has the potential to save lives. If you have sleep apnea, you are more likely to develop heart disease and abnormal heart rhythms like atrial fibrillation. By the time high blood pressure is recognized and treated, it often has already caused damage. But doctors don’t check for sleep apnea during a routine visit, and hypertension rarely has symptoms.  Being able to detect sleep apnea and hypertension at home with a simple device could prevent these common conditions from causing serious problems, and keep health care costs down in the process.