Careful with the sun

Tanning is natural?!

People think that exposure to UV radiation in tanning salons is less harmful, because you can control it. Lamps in tan beds usually produce UVA radiation. As we can see UVB is more dangerous, but that doesn't mean that this type of tanning is safe. Tanning indoors damages your skin. Overexposure to these rays can cause eye injury, premature wrinkling of the skin, and light-induced skin rashes, and can increase your chances of developing skin cancer


By MARIJA MITROVIĆ
from Belgrade, SERBIA


"Mother Nature had it right all along: Tanning is natural. It's what your body is designed to do. Just like you need air, food and water, you need sunlight to survive." You can read this words on web page which is dedicated to truth about tanning, which is maintained by Smart Tan Network, the professional tanning salon association. This statement seems truth-less. Without water and sun there would be no life on Earth, everybody knows that! But, someone is playing games with words. Yes, sun (sunlight) is very important, but tanning?! Is tanning really natural? What is tan?

The dark pigment that gives the skin its natural colour is called melanin. Melanin is made in the skin by pigment cells called melanocytes. After our skin is exposed to sunlight, the melanocytes make more melanin to try to absorb further UV radiation, and so the skin becomes darker. A tan is actually a sign that the skin has been damaged and is trying to protect itself. So, UV radiation is a part of sunlight that "gives" us a dark tan. Well, do You know what UV radiation is? Do You know how much harm it can done to You?

Dark tan "thanks" to UV radiation

The solar electromagnetic radiation is distributed over a wide range of wavelengths. Wavelengths shorter than 400 nm are known as the UV waveband and wavelengths longer than 700 nm are known as infrared radiation. The wavelengths of 400-700 nm are the visible waveband. In this visible waveband, the shorter wavelength corresponds to violet and the longer wavelength corresponds to red. The UV waveband is further sub-divided into the three wavebands, UVA (320-400 nm), UVB (280-320 nm) and UVC (100-280 nm). Part of spectrum between 40 nm-100nm is also a part of UV radiation but it never rich the Earth's surface. The natural protector from harmful UV radiation is ozone in upper atmosphere (stratosphere). UVC encounters ozone in the mid-stratosphere, it is quickly absorbed so that none reaches Earth's surface. But UVB is only partially absorbed and UVA is barely absorbed. About 95% of all UV radiation that reach the Earth is UVA.

UV radiation from the sun has always played important roles in our environment, and affects nearly all living organisms. Biological actions of many kinds have evolved to deal with it. Yet UV radiation at different wavelengths differs in its effects, and we have to live with the harmful effects as well as the helpful ones. Radiation at the longer UV wavelengths (UVA) was once thought to have a minor effect on skin damage, but now studies are showing that UVA is a major contributor to skin damage. UVA penetrates deeper into (longer wavelengths) the skin and works more efficiently. The intensity of UVA radiation is more constant than UVB without the variations during the day and throughout the year. UVA is also not filtered by glass. For decades, solar radiation in the UVB spectrum has been recognized as the primary etiologic agent of skin cancer.



During last few years, researchers realized that UVA can cause skin cancers, but the tumors take longer to develop and require much larger doses of light. Skin cancer is the most common human cancer and there is little dispute that chronic exposure to solar ultraviolet radiation is the most important cause of non-melanoma skin cancers (NMSC). The two common types of NMSC are basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). BCC accounts for about 80% of all NMSC. Epidemiological studies have shown that people who work outdoors are more likely to develop skin cancer than indoor workers. Application of multivariate analysis to the epidemiology of skin cancer has shown that age and environmental ultraviolet exposure are the two most important factors in determining the relative risk of NMSC. Beside NMSC, one more type of skin cancer is malignant melanoma. Malignant melanoma is a tumor derived from the pigment cells (melanocytes) of the skin. Unlike NMSC, melanomas have a marked tendency to metastasize. In 1945 the 5 year survival in the USA for people with melanoma was only 41% although by 1983 this had risen to 83%, presumably because of earlier detection and treatment. Unfortunately the improvement in prognosis is offset by a rapid rise in incidence so that the mortality rate continues to rise. In the USA melanoma incidence has almost doubled in the past decade, and in Sweden there was a five-fold increase in incidence between 1958 and 1984. Changing patterns of sun exposure are believed to be an important factor in the continuing rise in incidence. Although the evidence from epidemiological studies indicates an association between melanoma and sunlight exposure, it does not appear that cumulative sun exposure explains the relationship, as it does for NMSC. Instead, an intermittent exposure hypothesis proposes that infrequent intense exposure of unacclimatized skin to sunlight is related to increasing melanoma incidence and is more important than chronic sun exposure.

Think twice

Skin cancer is just one of harmful effects of UV radiation on human. Probably the most usual injuries are sunburns. Cause of sunburns is UVB radiation. During the day, maximum intensity of this type of UV is between 11 am and 4 pm. We can spent more time on sun during a early morning and late afternoon without fear of sunburns. But even than we risk photo-aging of our skin. The clinical signs of a photo-aged skin are dryness, deep wrinkles, accentuated skin furrows, sagging, loss of elasticity, mottled pigmentation and telangiectasia. These characteristics reflect profound structural changes in the dermis. Also, our eyes are in danger. Studies in experimental animals have confirmed that the development of certain types of cataract (opacity of the lens) are associated with ocular UVB exposure. A recent epidemiological study has found a similar response in humans. There are some studies that suggest that UVA can also have bad effects on human eye.

People think that exposure to UV radiation in tanning salons is less harmful, because you can control it. Lamps in tan beds usually produce UVA radiation. As we can see UVB is more dangerous, but that doesn't mean that this type of tanning is safe. Tanning indoors damages your skin. Overexposure to these rays can cause eye injury, premature wrinkling of the skin, and light-induced skin rashes, and can increase your chances of developing skin cancer.

So if you hear something like "Tanning is natural" think twice, maybe it is not. But don't be afraid of the sun, just be careful, very careful.