Updated: May 7, 2019
The general perception of a tan is coloration of the skin after sun exposure that increases with duration and intensity of sun exposure. However, there is more to it...
Tanning can be Immediate or Delayed or Sunless/UV-less.
Immediate tanning, also known as Immediate Pigment Darkening, is the immediate discolouration of the skin lasting for a few hours to few days then fading away
Delayed tanning develops 72 hours after UV exposure and lasts for several weeks
Sunless or UV-less tanning occurs with the use of certain chemicals such as Carotenoids or Dihydroxyacetone. It is known as Fake tanning or Bronzing. It must be noted that this does not protect the skin from sun unlike sunscreens
The Causes of Tanning
Sunlight consists of two types of radiation; one is visible light that ranges from red to blue and the other one is Ultraviolet radiation.
Ultraviolet radiation (UV) is implicated in many skin disorders and tanning. UV radiation can be subdivided into UV-A (320-400nm), UV-B (280-320nm) and UV-C (100-280nm). UV-A and UV-B are both responsible for immediate tanning while only UV-B produces delayed tanning. UV-C is the most harmful type of ultraviolet radiation and is filtered out by the ozone layer.
The Mechanism
As a natural protective response of the skin to avoid UV-induced damage to the deeper layers of skin, a pigment producing cell known as the Melanocyte is trigger by ultraviolet rays to produce increased amount of the pigment, Melanin. This melanin is then transferred to the popular skin cells known as Keratinocytes and thereby display color as light-brown to dark-brown. The melanin acts by absorbing UV rays and thereby preventing the passage of UV rays to deeper tissues. This is the case in delayed tanning.
Immediate tanning is however the result of a sudden chemical reaction of melanin present in keratinocytes thereby causing its oxidation and redistribution and manifesting as a color change. This accounts for the sudden appearance and resolution of immediate tanning.
Why is Tanning linked with Cancers?
The risk of cancers differ according to the skin type. Skin types are classed based on the skin color and the skin sensitivity to sun exposure as Skin types I to VI. Skin type I has the lightest skin color and most sensitivity to sun while Skin Type VI denotes the darkest skin with least sensitivity to sun.
Apart from tanning, UV exposure causes redness of the skin, changes in the genetic material (DNA) and depresses immune activity in the skin (immunosuppression). All these accentuate the risk of skin cancer.
Let's see the details how this comes to be. Redness is likened to irritation and inflammation of the skin. Constant episodes of inflammation results in morphoed and abnormal cells and thereby cancer.
The second point, that is DNA change, change in the genetic material of a cell alters the shape, replication rate of a cell and thereby increased altered growth.
Immunosuppression or depressed immune activity reduces our immune system's attack towards altered cancer cells thus allowing cells to increase in number and form cancer.
How to Avoid Tanning?
The Most Promising way to avert tanning is to avoid going out in the sun. To many this would sound impossible however we are referring to avoiding the peak hours of UV exposure which is usually 10 AM to 2 PM. This being the time UV rays are the strongest and most harmful.
Another way to block the UV exposure is by applying sunscreens. Sunscreens are of many types; Physical, Chemical or Systemic.
Physical sunscreens you may have seen on cricket players as a visible coat over the face which are formulated as zinc oxide or titanium dioxide.
Chemical sunscreens are used more commonly and denoted according to the Sun Protection Factor or SPF. A mere mention of SPF would not suffice as this is commonly misunderstood. To know more about SPF, refer our blog on Sun Protection Factor (What's the Right Technique for Applying Sunscreens), as it clarifies on the % and duration of sun protection achieved.
Systemic sunscreens are oral preparations of medications that produce a photoprotective effect. The thought of intake of medications that serve as sunscreens may be alarming however most of the chemical sunscreens are particular vitamins and minerals or natural substances such as beta-carotene (vitamin A), ascorbic acid (vitamin C), Green tea extracts and Selenium.
Tanning is not the only effect brought about by sun exposure. There are many other effects and diseases caused by sun exposure. It would be beneficial to keep in mind that an exposure of 20 - 30 mins daily is not harmful but beneficial i.e. for production of vitamin D. The harmful effects are the result of over exposure or by use of certain compounds that act as photosensitizers.
Let's take care of our skin and keep looking our best by avoiding too much sun exposure or if inevitable protect our skin by use of proper sunscreens under guidance of a dermatologist.
This information is brought to you by Specialized doctors in Al Arif Heart and Children Medical Center, Al Mujarrah, Sharjah, UAE. Keep yourselves fit as a fiddle.
#Tan #Tanning #Beauty #UVexposure #Sun #Protect #ProtectSkin #PhotoProtection #Sunscreen #Melanin #Melanocyte