As early as 1940, it was suggested that magnetic fields affect the TMP and the flow of ions in and out of the cells and might therefore influence cellular membrane permeability. It has since been established that magnetic fields can influence ATP (Adenosine Tri-phosphate) production; increase the supply of oxygen and nutrients via the vascular and lymphatic systems; improve the removal of waste via the lymphatic system; and help rebalance the distribution of ions across the cell membrane. Healthy cells in tissue have a voltage difference between the inner and outer membrane referred to as the membrane resting potential that ranges from -70 to -80 mV. This causes a steady flow of ions through its voltage-dependant ion channels. In a damaged cell, the potential is raised and an increased sodium inflow occurs. As a result, interstitial fluid is attracted to the inner cellular space, resulting in swelling and edema.

The application of PEMF to damaged cells accelerates the reestablishment of normal potentials (Sanseverino, 1999) increasing the rate of healing and reducing swelling. In biology, depolarization is a change in a cell's TMP, making it more positive or less negative. In neurons and some other cells, a large enough depolarization may result in an action potential. Hyperpolarization is the opposite of depolarization and inhibits the rise of an action potential. If a cell has a resting potential of -70mV and the membrane potential rises to -50mV, then the cell has been depolarized. Depolarization is often caused by influx of cations, e.g., Na+ through Na+ channels, or Ca2+ through Ca2+ channels. On the other hand, efflux of K+ through K+ channels inhibits depolarization, as does influx of Cl- (an anion) through Cl- channels. If a cell has K+ or Cl- currents at rest, then inhibition of those currents will also result in a depolarization. As the magnetic field created fluctuates, it induces an electron flow or a current in one direction through the living tissue. As electrons always flow from a negative (cathode) to a positive (anode) potential, when the magnetic field vanishes, the direction of the electron flow is reversed. Therefore such induced polarized currents stimulate the exchange of ions across the cell membrane. As the electromagnetic field pulses temporarily hyperpolarize and depolarize the membrane, the ion channels open and close allowing a more efficient ion exchange, as with the sodium-potassium (Na+, K+) pump, thus increasing cellular oxygenation and nutrition as sodium export stimulates several secondary active transporters.