Risks and Benefits of using sunbeds
Risks
Artificial tanning from UV exposure is known to cause cancer, make skin age and wrinkle faster, mutate DNA, and reduce the immune system, as well as other possible effects. These problems are believed to be worse from tanning in a tanning bed or sunbed than from the sun, due to the different intensity and spectrum of the artificial light. Specifically:
The US Public Health Service states that UV radiation, including the use of sun lamps and sun beds are "known to be a human carcinogen [=cancer causing agent]." It further states that the risk of developing cancer in the years after exposure is greatest in people under 30 years old. There is persuasive evidence that each of the three main types of skin cancer, basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and melanoma, is caused by sun exposure. Women who visited a tanning parlor at least once a month were 55% more likely to later develop melanoma than women who didn't artificially suntan. Young women who used sun lamps for tanning while in their 20s had the largest increase in subsequent cancer risk -- about 150% higher than similar women who did not use tanning beds.
Exposure to ultraviolet radiation induces at least two common genetic mutations. Those include cyclobutane–pyrimidine dimers (CPDs) and 6–4 photo products (6–4PPs) and their Dewar valence isomers. The mutation types generally differ between UVA and UVB light. Mutant cells may die, or become cancerous, depending on which genes were mutated. While DNA repair enzymes can fix some mutations, they are not sufficiently effective, as demonstrated by the relation to cancer, aging and other types of persistent mutation and cell death. For example, squamous cell carcinoma (a type of skin cancer) is caused by a UVB induced mutation in the p53 gene. These mutations are sufficiently common and rapid that testing mutation rates from tanning beds is sometimes suggested as an introductory biology experiment.
UVA light specifically, (sometimes called 'bronzing light') is clearly associated with increased skin aging and wrinkle production. This is because UVA penetrates the skin more deeply than UVB, and therefore causes damage on a deeper level. Most aging of skin is due to UVA rays destroying collagen and connective tissue beneath the superficial layer of the skin. UVB rays do not reach as far below the skin. Excessive exposure to UVA radiation has its risks, which may cause premature aging, including wrinkles, sunspots, and loss of skin elasticity.
Exposure to UV radiation also has a detrimental effect on the immune system. Exposure changes antigen presentation by Langerhans cells and macrophages. Also, the activities of natural killer cells and T cells is reduced. Last, cytokine regulation is disrupted by UV exposure. Ultraviolet radiation exposure may facilitate the growth of skin neoplasms and the spreading of skin-associated infections due to stimulation of suppressor T cells.
Using a sunbed without goggles may lead to a condition known as arc eye.
Although rare, it is possible for tanning beds to be a vector for infections of pubic lice, also known as crabs. If the surface of the bed is not properly cleaned or if towels provided by the salon are not washed in hot water, crab lice can survive for several days on these surfaces. Crab lice are difficult to see on the acrylic of a dimly lit tanning bed, and they are not killed by anti-bacterial or anti-viral cleaning agents used in salons.[citation needed] They can only be killed by physical removal or by the use of insecticides such as pyrethrin.
One study conducted amongst a college student population found that awareness of the risks of tanning beds did not deter the students from using them.
Tanning Beds vs. Natural Sunlight
Tanning beds have about 3-8 times greater UVA than sunlight (as opposed to UVB), while the 'warning signs' of overexposure, such as sunburn, do not appear at the same rate indoors as out. Furthermore, the radiation levels are more intense, requiring individuals to limit their exposure to very brief periods. The carcinogenic mutations in some skin cancers have been linked to UVA radiation more than UVB, suggesting that beds have different risks than natural light. The UVA light is also more strongly associated with skin aging than UVB, and with genetic damage.
Natural sunlight exposure has made studies of artificial tanning difficult, since many people are exposed to both. There are indisputable values to moderate sunlight exposure. UVB light induces the body to synthesize Vitamin D. Vitamin D is required for calcium absorption, and improves development and reduces cancer risk. The amount of sunlight required, however, is estimated to be less than a single tanning session provides (10 minutes of strong sunlight for many people).
Benefits
The benefits of artificial tanning are generally related to enjoyment and speed.
Tanning makes most people feel good. To understand how this happens, researchers set out to determine if endorphin levels were increased after tanning. They concluded that there were no significant differences in the mean plasma levels of β-endorphin between people who were exposed to tanning beds and those who were not. The positive psychological benefits of tanning may be due to factors other than endorphins.
While a tan that is developed in a tanning bed does offer some protection from overexposure to the natural sun, it is more cosmetic than a natural tan. A tan provides a natural SPF of between 2 and 4 (sun protective lotions are generally SPF 30 or higher). Depending on the intensity of the sun outside, it may be advisable to use additional lotion with SPF even if a base tan is present.
A more controversial benefit of tanning indoors rather than tanning outside is the amount of control the tanner has. If a person decides to get a suntan and wants to minimize the risk of getting a sunburn, a tanning bed offers an environment that delivers the same amount of UV in a given period of time, day after day. In contrast, the amount of UV that reaches the ground can vary from minute to minute and the longer tanning times results in deeper exposure. This doesn't make the tan in a tanning bed safer per se, but it can reduce the chance of a sunburn as it allows total control over the amount of exposure a person receives.
Tanning beds also offer time savings when compared to tanning outdoors. Most tanning beds offer a maximum session time of 20 minutes and a person can maintain a tan with 1 to 2 sessions per week. For individuals living in urban areas, or who work extended hours, a tanning bed may be the only opportunity for tanning or UV exposure of any kind.
A frequently mentioned benefit of artificial tanning is the increased production of Vitamin D. This vitamin has many benfits, and many people with indoor lifestyles may not receive enough. However, because tanning beds use bulbs with low UVB relative to UVA production, or relative to sunlight, they offer limited value in the production of vitamin D.
It is believed that indoor tanning beds are useful for the treatment of SAD (Seasonal Affective Disorder), though this is disputed at present.[30] It is plausible that the benefit that many SAD patients experience are more due to tanning causing them to feel good in general, rather than treating the SAD itself.
Source: Wikipedia