This systematic review evaluated evidence on RF-EMF exposure and cardiac activity (heart rate and heart rate variability) in healthy humans at rest. Across 28 studies spanning 100 to 110,000 MHz and exposures from minutes to a week, most studies reported no significant effects on resting heart rate, and HRV findings were largely null under calm conditions. Some position-dependent HRV changes were reported, and the authors note possible effects during physiological challenges, but conclude evidence is insufficient for firm conclusions beyond resting healthy populations.