Researchers tested the magnetic field output of common smartphones and smart watches at varying distances from implanted heart devices and discovered that in close proximity (less than 6 inches), the magnetic fields of these devices were strong enough to potentially interfere with implanted defibrillators and pacemakers. Based on the findings, study author Dr. Seth Seidman notes, “[Patients should] take simple proactive and preventive measures, like keeping consumer electronics, such as certain cellphones and smart watches, six inches away from implanted medical devices and not carrying consumer electronics in a pocket over the medical device.” Heart Rhythm, August 2021