You may not know this but your brain actually communicated with your body in the same way that electricity is conducted through a wire. The electrical impulses created by your brain are sent through your nervous system to the various parts of the body that it needs to do something. If you need to sit up or take a walk around the room, your brain uses your motor neurons to control and communicate with your muscles to make them do what they are supposed to. That whole concept is the basis for using a Tens machine in the first place. Even though the theory is sound, electrical nerve stimulation is often a heated debate amongst health practitioners, and is mainly due to a few inconsistencies in the results.