Which beat frequency is commonly used in IFC to provide conventional pain relief?

• A. 80–100 Hz
• B. 1–10 Hz
• C. 50 Hz
• D. 20–30 Hz

Answer: (A)

Interferential current therapy relies on two medium-frequency currents that intersect to produce a beat frequency, which is the rate at which the neural tissue is modulated to relieve pain. For conventional pain relief, the beat frequency is set high—around 80 to 100 Hz—because this range activates fast-dacting A-beta fibers that inhibit pain transmission at the spinal level through the gate control mechanism. The result is rapid, comfortable analgesia suitable for general, non-specific pain.

Lower beat frequencies, like 1–10 Hz, are used when aiming for acupuncture-like analgesia mediated by endogenous opioids, which tends to have a slower onset. Frequencies in other ranges (such as 20–30 Hz or 50 Hz) are typically associated with different therapeutic aims, like muscle stimulation or other effects, rather than standard conventional pain relief.