Purpose: To trasnmit and receive radio signals. There are two main bands - AM (amplitude modulation) and FM (frequency modulation) (see above).
Issue: Although these frequencines have been in use for decades, their strength, and your proximity to the signal, can have physical consequences (see millimeter wave technology).
Better Option: The strength of your transmitter/receiver is key here. If you are near a strong transmitter (the WHAS AM transmitter, for example), then your best option is to physically distance yourself from it. Weaker transmitters/receivers (such as battery powered radios or walkie talkies) are less stressful on the body. Conscientious use (distace from electric and magnetic fields) is key here as these devices may be reuired to communicate.