This number is larger than typical AC electric power magnetic fields, but DC fields do not create currents in objects in the way that AC fields do. A. AC fields create weak electric currents in the bodies of people and animals. This is one reason why there is a potential for EMFs to cause biological effects. As shown on the right, currents from electric and magnetic fields are distributed differently within the body. Currents from 60-Hz EMFs are weaker than natural currents in the body, such as those from the electrical activity of the brain and heart.
Some scientists argue that it is therefore impossible for EMFs to have any important effects.
In most cases, however, it is not clear how EMFs actually produce these demonstrated effects. Strong electric fields, such as those found beneath large transmission lines, can cause hair on your exposed head or arms to vibrate slightly at 60 Hz. This is felt by some people as a tingling sensation. EMFs from transmission lines can also in some circumstances cause nuisance shocks from voltages created by EMFs on objects like ungrounded metal fences.