Sun tanning
The tanning process can be triggered by natural sunlight or by artificial UV radiation, which can be delivered in frequencies of UVA, UVB, or a combination of both.
[9] In the second process, triggered primarily by UVB, there is an increase in production of melanin (melanogenesis),[10] which is the body's reaction to direct DNA photodamage (formation of pyrimidine dimers) from UV radiation.
An individual's natural skin color can vary from a dark brown to a nearly colorless pigmentation, which may appear white.
This can be alleviated at least to some extent by the prior application of a suitable-strength sunscreen, which also hinders the tanning process due to the blocking of UV light.
[22] Frequent tanning bed use triples the risk of developing melanoma, the deadliest form of skin cancer, according to a 2010 study.
The study suggests that the melanoma risk is linked more closely to total exposure than it is to the age at which an individual first uses a tanning bed.
[23] Frequent tanning also has behavioural reinforcing effects,[24] following UVA radiation epidermal keratinocytes synthesize POMC inducing the production of β-Endorphins, which are opioid agonists.
An opioid blockade also then causes withdrawal signs after habitual UV exposure leading to many tanners meeting the DSM-IV criteria for addiction.
[33] In the United States and Western Europe before the 1920s, tanned skin was associated with the lower classes because they worked outdoors and were exposed to the sunlight.
In 1910 a scientific expedition went to the island of Tenerife to test the wider health benefits of "heliotherapy",[37] and by 1913 "sunbathing" was referred to as a desirable activity for the leisured class.
In addition, Parisians fell in love with Josephine Baker, a "caramel-skinned" singer in Paris, and idolized her darker skin.
Coppertone, in 1953, marketed its sunscreen with a drawing of a young girl and her cocker spaniel tugging on her bathing suit bottom, revealing her bare bottom and tan line; this advertisement was modified around the turn of the 21st century and now shows a little girl wearing a one-piece bathing suit or shorts.
As recently as 2012, in some parts of China, ski masks were becoming popular items to wear at the beach in order to protect the wearer's face from the effects of sunlight.
Tan-through swimwear typically allows more than one-third of UV rays to pass through (equivalent to SPF 3 or less), and an application of sunscreen even to the covered area is recommended.
[49][50][51] To avoid exposure to UVB and UVA rays, or in seasons without strong sunshine, some people take alternative steps to appear with darkened skin.
[citation needed] Many sunless tanning products are available in the form of darkening creams, gels, lotions, and sprays that are self-applied on the skin.
