Sun tanning or simply tanning is the process whereby skin color is darkened or tanned. It is most often a result of exposure to ultraviolet (UV) radiation from the sun or from artificial sources, such as a tanning bed. People who deliberately tan their skin by exposure to the sun engage in a passive recreational activity of sun bathing. Some people use chemical products which can produce a tanning effect without exposure to ultraviolet radiation.
Moderate exposure to the sun contributes to the production of vitamin D by the body, but excessive exposure to ultraviolet rays has negative health effects, including sunburn and increased risk of skin cancer, [1] as well as depressed immune system function and accelerated ageing of the skin.[citation needed] Some people tan or sunburn more easily than others. This may be the result of different skin types and natural skin color, and these may be a result of genetics.
Several cases of tanning addiction have been reported. Though the mechanism by which tanning addiction occurs is unknown, some evidence indicates that the release of endorphins during the tanning process causes the pleasurable effects that underlie the addiction.[2]
The term "tanning" has a cultural origin, arising from the color tan. Its origin lies in the Western culture of Europe when it became fashionable for young women to seek a less pale complexion (see Cultural history below).