Which TENS settings are typical for chronic pain?

• A. High frequency 50–100 Hz and short pulse width
• B. Randomized frequency and width
• C. Low frequency 2–10 Hz and longer pulse width
• D. Moderate frequency 15–30 Hz and very short pulse width

Answer: (C)

For chronic pain, the goal is to induce longer-lasting relief by engaging the body’s own analgesic systems. Low-frequency TENS around 2–10 Hz with a longer pulse width accomplishes this by triggering endogenous opioid mechanisms in the central nervous system, producing analgesia that can outlast the stimulation session. The longer pulse width helps recruit deeper nerve fibers necessary to activate these pathways, which is why this pattern is favored for persistent pain.

High-frequency TENS (50–100 Hz) with a short pulse width tends to provide quick, momentary relief via the gate-control mechanism but doesn’t usually give the same extended benefit for chronic pain. Randomizing frequency and width lacks consistency in analgesic effect, and a moderate frequency with a very short pulse width doesn’t effectively engage the opioid-mediated pathways needed for lasting relief.