The fundamental physics principle behind how PEMF works: a changing magnetic field creates an electric field in any nearby conductor, including the fluids and cells of the body. The faster the magnetic field changes, the stronger the induced electric field. This means the biological effect of a PEMF pulse depends heavily on how quickly the field rises and falls, not just on how strong it is at its peak. Two settings with the same peak Gauss but different rise times will produce very different levels of tissue stimulation.
A magnetic field that changes in time induces an electric field in the tissue it passes through. This is Faraday's law, and it is why the speed of the field change (the slew rate) matters more than the field's peak strength: a faster change induces a stronger electric field, which is what stimulates the body.
