Interferential current therapy works by sending small amounts of electrical stimulation to damaged tissues in the body. The therapy is meant to boost the body's natural process of responding to pain, by increasing circulation thus produces hormones that promote healing. IFT delivers intermittent pulses to stimulate surface nerves and block the pain signal, by delivering continuous deep stimulation into the affected tissue. IFT relieves pain, increases circulation, decreases edema, and stimulates the muscles. A frequency of 100Hz may stimulate the large diameter A-beta fibers, which have an effect on the pain gate, and inhibit the transmission of small-diameter nociceptive traffic ( C and A-delta fiber), which effectively closes the gait to painful impulses. Interferential current Increases the circulation of blood thus reduces swelling, by washing away the chemicals that stimulate the nociceptive nerve endings.
The frequency between 1 and 100 Hz is used to contract the normal innervated muscles. Different types of frequencies cause different contractions, a low frequency, causes a twitch, frequency between 5 and 20 Hz causes a partial tetany contraction and frequency from 30 to 100 Hz causes a tetanic contraction. IFT also helps to reduce edema 100Hz frequency promotes vasodilation, thus decreases edema. And a frequency of 10 Hz activates the musculoskeletal pump, used to promote venous and lymphatic return causing reduction of edema. The neurons that make the autonomic nervous system, are small and poorly myelinated like the Aδ and C fibers of the peripheral nervous system and to stimulate the autonomic nervous system, lower frequencies are utilized to increase the blood flow.