Is sunbathing good for you
- Pages: 7
- Word count: 1559
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Many people sunbathe to look attractive. Also to relax and generally get a tan. But a lot of people don’t know the science behind sunbathing. When sunbathing, ultra violet radiation enters your body as the skin absorbs it. Too much of this can cause damage and even cause you skin cancer.
The diagram on the left shows and intersection of the sun and the different layers within the inside.
In the electromagnetic spectrum the shorter the wavelength, the more energetic the radiation and the greater the potential for harm.
Ultra violet waves are electromagnetic waves. It is a form of energy travelling through space. This is the portion of the electromagnetic spectrum extending from the violet, or short-wavelength, end of the visible light range to the X-ray region. Ultraviolet radiation is invisible to the human eye.
The sun is a major source of ultraviolet rays. Though the sun emits all of the different kinds of electromagnetic radiation, 99% of its rays are in the form of visible light, ultraviolet rays, and infrared rays (also known as heat). Man-made lamps can also emit UV radiation, and are often used for experimental purposes.
Light enables us to see, and heat keeps us from being cold. However, ultraviolet rays often carry the unfortunate circumstance of containing too much energy. For example, infrared rays create heat in much the same way as rubbing your hands together does. The energy contained in the infrared rays causes the molecules of the substance it hits to vibrate back and forth.
However, the energy contained in ultraviolet rays is higher, so instead of just causing the molecules to shake, it actually can knock electrons away from the atoms, or causes molecules to split. This results in a change in the chemical structure of the molecule. This change is especially detrimental to living organisms, as it can cause cell damage and deformities by actually mutating its genetic code.
Vitamin D from sunlight
Human skin absorbs sunlight to make vitamin D. Vitamin D helps us by strengthening our muscles and bones. Also it boosts our immune system and this can protect us from infection. Recent research also suggest that vitamin D can prevent the growth and spread of cancer in the breast, colon, ovary, and other organs. (Twenty first century science)
These are all benefits of ultraviolet light from sunlight, but will only good in moderation.
Does ultraviolet light cause any harm?
There are different viewpoints from scientists
regarding this question.
These are two opposing statements. They both support their opinions by either using evidence or just reasons.
What should people be aware of?
We should all try not to get burnt in the sun and to be aware of the damage it can do to our skin. But some people need to be particularly careful. You should be particularly careful about going out in the sun if you:
* Are fair skinned
* Have lots of moles
* Have a close relative who has had melanoma
Melanin in the skin
Human skin colour can range from almost black to nearly colorless (appearing pinkish white due to the blood in the skin) in different people. The colour of skin depends primarily on a pigment called melanin. It is also influenced by the blood flow through the skin. Melanin is a pigment produced by special cells called melanocytes that manufacture packets of melanin called melanosomes and transfer them to the skin cells of the epidermis the keratinocytes.
In general, people with ancestors from tropical regions (hence greater sunlight exposure) have darker skin than people with ancestors from subtropical regions.
Melanin pigmentation in humans is of two types. The constitutive colour is that which is genetically determined without the effect of sunshine. The other is inducible skin colour or tan as a consequence of sun exposure. Other factors can darken skin, some hormones e.g. in pregnancy can make the skin darken and some parts of the body are darker than others. In white people the darkest area is the upper thigh and the lower back is the lightest. In black people the abdomen is the darkest. Melanin helps protect the skin against the effects of ultraviolet light, and tanning of the skin on sun exposure acts to increase that protection.
Health related effects
Dark skin protects against ultraviolet light; this light causes mutations in skin cells, which in turn cause skin cancers. Light-skinned people have a greater risk of dying from skin cancer under equal sunlight exposure, with redheads having the greatest risk.
Sciencedaily (Oct. 18, 2004) – Blondes and redheads not only are more susceptible to skin cancer, but the source of their skin and hair pigmentation, melanin, actually magnifies the damaging effects of ultraviolet (UV) rays, according to a study published online this week in the Proceedings of the National Academy of Sciences.
Sun tanning occurs because exposure to sunlight causes the skin to produce more melanin and to darken. The tan fades as these cells move toward the surface and are sloughed off. Too much exposure to ultraviolet or UV rays can cause sunburn. UV rays penetrate the outer skin layers and pass into the deeper layers, where they can damage or kill skin cells. Frequent and prolonged exposure to ultraviolet rays over many years is the chief cause of skin cancer.
Skin cancer is one of the most common cancers in the UK and the number of people who get it is increasing. Most skin cancers are caused by damage from UV (ultraviolet) rays in sunlight. They mutate our DNA. These cancers could be prevented if we protect ourselves from the sun.
* There are over 75,000 new cases of skin cancer diagnosed each year in the UK.
* Many cases are not reported so the real number of cases is probably much higher.
* The number of cases has almost tripled since the early 80s.
* Over 2,300 people die from skin cancer each year in the UK.
There are more skin cancer deaths in the UK than in Australia, even though Australia has more cases of the disease and is a much hotter climate.
One of the most commom types of skin cancer is called Melanoma. melanoma develops when normal pigment-producing skin cells called melanocytes become abnormal, grow uncontrollably, and invade surrounding tissues. Usually only one melanoma develops at a time. Although melanomas can begin in an existing mole or other skin growth, most start in previously unmarked skin. Melanoma is classified as primary or metastatic.
Ultraviolet light (UVA and UVB) from the sun is the main cause of most skin cancers.
Skin cancer is becoming more common and there are several possible reasons for this. People are living longer (and so their lifetime sun exposure is greater). They often have more time and money for outdoor recreation and holidays in sunny climates, and many people still consider suntans to be healthy and attractive. People who work outdoors for a living, such as farm workers, builders and gardeners, are at an increased risk of developing skin cancer because of prolonged exposure to the sun. It is likely that most skin damage from ultraviolet radiation occurs before the age of 20.
The Melanoma Unit in Sydney is the largest treatment centre for melanoma in the world. Two studies into the causes of melanoma are being carried out by the Unit. One is a study of the relationship between mole formation in children and their exposure to sunlight. The other is a study into the genetic causes of melanoma.
“One of the interesting projects that we are doing at the moment,” says Bill McCarthy, (Head of the Sydney melanoma unit at Royal Prince Alfred Hospital) “is to look at groups of children between the ages of 6 and 15 living in cities that have different levels of UV light. We are looking at a group of children in Melbourne, a group in Sydney and a group in Townsville. The sunlight is much more intense in Townsville than it is in Melbourne. We have assembled groups of 100 six year olds, 100 nine year olds, 100 twelve year olds and 100 fifteen year olds in each of these three cities. We start by counting their moles and then we compare the number of moles on children of the same age groups in the different cities. The children selected for the survey are all of fair skinned genetic origin.”
There are 6 times more moles on children in Townsville, for instance, than there are in Melbourne. This is a big difference which is unlikely to be due to chance. There is no doubt that the incidence of exposure to sunlight is much greater in 6 year old children living in Townsville than for similar children living in Melbourne. The results seem to confirm that childhood exposure to sunlight is responsible for the formation of moles.
The project involves monitoring the general levels of UV light in each city while at the same time a subgroup of the children are actually monitoring their own exposure to sunlight.
Sunbathing is something that most people like to do. It is proven that being in the sun generally makes people happier. There is evidence for sunbathing being good but also bad. I feel that sunbathing is good for you in moderation. You get vitamin D from the sun and that strengthens our bones and muscles. However we should really take into account the risks involved in sunbathing and always take caution when doing so. ALARA ( as low as reasonably achievable) or the precautionary principle should be the approach towards this topic.