Apart from energy absorption and especially below 10 MHz, what is the second established adverse health effect described in Safety Code 6?

Safety Code 6 identifies two primary mechanisms by which RF energy interacts with the human body. At higher frequencies, the primary concern is tissue heating (thermal effects) due to the body absorbing RF energy. However, at lower frequencies, particularly below 10 MHz, the RF fields interact differently. They can induce electric currents within the body instead of just heating it. These induced currents can cause nerve and muscle stimulation, leading to a tingling sensation or muscle contractions. Options like nausea, numbness, or skin redness are not established direct mechanisms for low-frequency RF exposure described in the code.