A first-of-its-kind study has found that wearable fitness and wellness trackers could interfere with cardiac devices.

The study, published in the journal Heart Rhythm, found “bioimpedance technology” in devices such as smartwatches, smart rings, and smart scales can interfere with the functioning of cardiac implantable electronic devices (CIEDs) such as pacemakers, implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy (CRT) devices.

In the study, researchers found the electrical current used in wearable smart devices during bioimpedance sensing interfered with the functioning of some implanted cardiac devices from three leading manufacturers.

In bioimpedance sensing technology, the device emits a small, imperceptible electrical current to measure different body metrics, including the level of body fat, muscle mass, stress levels, and breathing rate. In addition to this, wearable fitness trackers also record measurements such as the number of steps taken, heart rate, blood pressure, calories burned, and sleep cycle via this technology.

“Bioimpedance sensing generated an electrical interference that exceeded Food and Drug Administration-accepted guidelines and interfered with proper CIED functioning,” lead researcher, Dr. Benjamin Sanchez Terrones, of the University of Utah, said, The Guardian reported.

However, the results do not translate into any immediate risks to patients who wear the trackers, Sanchez said. Nevertheless, the different levels of electrical current sent by the smart devices could result in unnecessary shocks to the heart, he added.

“Our findings call for future clinical studies examining patients with CIEDs and wearables,” Sanchez noted.

While the association between general electrical appliances and CIEDs has received attention from researchers in recent years, this is the first study to analyze devices that use bioimpedance sensing technology and their potential interference with CIEDs.

“Our research is the first to study devices that employ bioimpedance-sensing technology as well as discover potential interference problems with CIEDs such as CRT devices. We need to test across a broader cohort of devices and in patients with these devices. Collaborative investigation between researchers and industry would be helpful for keeping patients safe,” Sanchez said.

Patients with implantable cardiac devices are cautioned about possible interference with different electronics due to magnetic fields. Patients are advised against keeping a mobile phone in a breast pocket near a pacemaker, for instance.

“As more people wear smartwatches and other devices with body-monitoring technology, it is important to understand any potential interference they may cause with lifesaving medical devices like ICDs and pacemakers,” Prof James Leiper, an associate medical director at the British Heart Foundation, said, as per the outlet.

“This study is the first step in this process. However, more research needs to be done in this area to understand any effects on patients,” Leiper added.