The effects of different types of current on the organism

The body's aqueous environment contains ions - an electrolyte. Direct current therefore has electrolytic effects on the body, and current densities of around 0.5 mA/cm 2 can cause serious tissue damage.

Alternating low-frequency (50–500 Hz) current has only weak electrolytic effects because the polarity of the electrodes alternates periodically. However, it has significant irritating effects, which are manifested on the muscle by its twitching (and when it passes through the heart muscle , it can cause it to stop).

Alternating high-frequency current has no electrolytic effects, and at frequencies above 100 kHz, there are no irritating effects at all. Thermal effects are fully applied here.