Fig. 8.

The surface of the earth has an abundance of electrons that give it a negative electrical charge. Left, if you are standing outside on a clear day, wearing shoes or standing on an insulating surface like a wood or vinyl floor or asphalt, there is an electrical charge of some 200 V between the Earth and the top of your head. Right, if you are standing outside in your bare feet or wearing conductive shoes, your whole body is in electrical contact with the Earth's surface. Your body is a relatively good conductor. Your skin and the Earth's surface make a continuous charged surface with the same electrical potential. Also, notice in the diagram on the right that the charged area is pushed up and away from your head if you are grounded. Any object in direct contact with the earth-a person, a dog, or a tree-creates this shielding effect. The object is essentially residing within the protective “umbrella” of earth's natural electric field. This protective phenomenon also occurs inside your house or office if you are connected to the earth with an earthing device, such as a grounding wrist pad or a foot pad. Reproduced from Ober C, Sinatra ST, Zucker M. Earthing: The Most Important Health Discovery Ever? Laguna Beach, CA: Basic Health Publications; Second Edition, 2014, p. 76 [63].