Archive for January, 2013

Sunny Health

January 15, 2013

There are many forms of sun damage. The most common are: sunburn or a sun tan. Both of these lead to premature aging of the skin and skin cancers. Both are symptoms of sun damage.  Each year there are more new cases of skin cancer than the combined incidence of cancers of the breast, prostate, lung and colon.

The sun gives off a range of light rays composed of different elements: cosmic rays, gamma rays, X-rays, ultraviolet rays (UV) (comprising UVA, UVB and UVC rays), visible rays, infrared rays (IR) and radio waves.

After being filtered by the atmosphere, two-thirds of these rays reach the earth. Cosmic rays, gamma rays, X-rays and UVC rays, incompatible with life, do not reach the surface of the earth. Among the rays that reach us, only the UVA, UVB, visible and infrared rays have an effect on our bodies.

These rays do have beneficial effects: UVB rays help us to produce vitamin D, essential for fixing calcium in the bones, visible light has an antidepressant effect and infrared rays have a heating action which leads to a rise in skin temperature (an alarm signal to help us avoid sunburn).

However, in the event of overexposure to the sun, the UVA and UVB rays can be particularly damaging. In the short term, they can cause sunburn and trigger photo-sensitization reactions (pathological skin symptoms linked to the interaction in the skin of an external agent and the sun). Over longer periods, UVA and UVB rays are responsible for cutaneous ageing and especially for the emergence of skin cancer.

Basal cell carcinoma (BCC) is the most common form of skin cancer; about one million of the cases diagnosed annually are basal cell carcinomas. Basal cell carcinomas are rarely fatal, but can be highly disfiguring.  Squamous cell carcinoma (SCC) is the second most common form of skin cancer. More than 250,000 cases are diagnosed each year, resulting in approximately 2,500 deaths.  The most harmful type is melanoma.  While melanoma is uncommon in African Americans, Latinos, and Asians, it is frequently fatal for these populations.

Here are some sun-safety habits that really work:

* Seek the shade, especially between 10 A.M. and 4 P.M.

* Do not burn.

* Use a sunscreen with an SPF of 15 or higher every day.

* Apply 1 ounce (2 tablespoons) of sunscreen to your entire body 30 minutes before going outside. Reapply every two hours or immediately after swimming or excessive sweating.

* Cover up with clothing, including a broad-brimmed hat and UV-blocking sunglasses.  Then again, some UV rays will still reach you through your close. Look for UPF rating of 40-50+ clothing.

* Keep newborns out of the sun. Sunscreens should be used on babies over the age of six months.

* Examine your skin head-to-toe every month.

* See your doctor every year for a professional skin exam.

* Avoid tanning and UV tanning salons.

MOST SENSITIVE PARTS: ears, nose, lips, neck, shoulders, upper back, nape of the neck, backs of the knees, calves and feet.

Opt for shade rather than sun, while remembering that the former does not represent total protection. Indeed, shade offers protection against the sun’s direct rays but not against the sun’s rays reflected off the ground (grass reflects 3% of the UV rays hitting it, sand between 5% and 25%, snow 30% to 80% and water 5% to 90%), and not against the sun’s rays diffused by particles suspended in the atmosphere (at midday, 30% to 50% of UV rays on the skin are rays diffused by atmospheric molecules).

The Sun Protection Factor (SPF) represents a time factor that delays the appearance of sunburn under standardized conditions: under sun giving off UVB and UVA rays and for a quantity of 2 mg/cm² of photo-protective product applied on the skin.

If the skin becomes sunburned, without protection, after 15 minutes’ exposure, with a SPF 10 photo-protective product, this will only occur after 10 x 15 minutes, i.e. 150 minutes, under the same exposure conditions.

But there are problems with the SPF model: First, no sunscreen, regardless of strength, should be expected to stay effective longer than two hours without reapplication. Second, “reddening” of the skin is a reaction to UVB rays alone and tells you little about what UVA damage you may be getting. Plenty of damage can be done without the red flag of sunburn being raised.

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