Friday, 18th May 2012
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Sun Protection

What is sun protection?
Sun protection is defense against the adverse effects of sunlight, which is the natural source of ultraviolet (UV) radiation that can cause damage to the skin in numerous ways – sunburn, freckles, premature signs of ageing, and skin cancer.

Skin cancer is on the rise and the major risk factor is, of course, the sun’s ultraviolet radiation.   More than one million Americans develop skin cancer each year. [1] Many studies have found that sunburns can cause an increased risk in the development of melanoma, [2] the deadliest form of skin cancer.

What are UVA and UVB rays?

Sunlight emits two types of harmful rays, UVA and UVB radiation.  UVA rays can penetrate into the deeper layers of the skin and can lead to signs of premature ageing, while UVB rays can burn the skin.  Too much exposure to both UVA and UVB rays can lead to skin cancer.

Who are more susceptible to sun damage?

People with light skin are more susceptible to sun damage, but dark skinned people can also be affected.  It is important to wear sun protection regardless of age and skin type to avoid the damaging effects of sunlight.

When to apply sunscreen

Regardless of the season, sunscreen should be applied daily.  Even on cloudy days, UV radiation remains high as sunlight is able to penetrate through the clouds.  Snow reflects as much as 80% of UV rays, sand about 15%, and sea foam about 25%.[3] In indoors, UV radiation is also present through incandescent and fluorescent lights, and other artificial sources.

When/how to avoid sunlight

The sun peaks at around 10 am to 4 pm, so avoid staying on the outdoors for too long during this timeframe.  When going outdoors, try to get as much shade by walking under a shaded area.  Shade can reduce UV radiation by as much as 50%.[3] Other ways to protect your skin from direct sunlight include using an umbrella, wearing protective clothing, hat, and sunglasses.

References:

  1. http://www.cancer.org/docroot/PED/content/ped_7_1_Skin_Cancer_Detection_What_You_Can_Do.asp?sitearea=PED
  2. http://www.aad.org/media/background/factsheets/fact_sunscreen.htm – Elwood JM, Jopson J. Melanoma and sun exposure: an overview of published studies. Int J Cancer (1997). 73(2):198-203.
  3. http://www.who.int/uv/publications/en/UVIGuide.pdf

Proper Application of Sunscreen

So how do we protect ourselves from the sun’s harmful rays?  According to the American Academy of Dermatology, we should, regardless of skin type, make it a daily habit to wear water-resistant sunscreen that gives protection from UVA and UVB rays, and contains Sun Protection Factor (SPF) of at least 30.

Sunscreens come in many different forms – creams, lotions, gels, even in makeup.  Be sure to check the label to know how much protection you’re getting.  Also, read the guidelines written on the back of the container to maximize the effectiveness of the product.

  • Application.  Sunscreen should be applied 30 minutes before sun exposure.  Apply a liberal amount of sunscreen to all the exposed areas of the body with particular attention to the face, ears, hands and arms.  Reapply every 2 hours or after heavy perspiration and swimming.
  • Difference between a chemical and physical sunscreen.  A chemical sunscreen is absorbed into the skin.  It eliminates UV radiation upon contact with the chemicals.  A physical sunscreen is chemical-free and works by reflecting UV rays.  It’s like putting a barrier between your skin and the sunlight.  Physical sunscreens do not cause skin irritations and allergies because they are not absorbed into the skin.  Either way, you get protection from UV radiation.
  • Ingredients.  Physical sunscreens usually contain zinc oxide and titanium dioxide.  Chemical sunscreens contain padimate O, homosalate, octyl methoxycinnamate, benzophenone, octyl salicylate, phenylbenzimidazole sulfonic acid, and octocrylene. [1]
  • Protection.  Broad-spectrum sunscreens protect you from both UVA and UVB rays.
  • SPF.  SPF is only applicable to UVB radiation.  The higher the SPF, the stronger the protection against UVB rays.  Higher SPF does not increase the length of time you stay protected.  SPF 15 gives you about 93% of protection against UVB rays, SPF 30 about 97%, SPF 50 about 98%, and SPF 100 about 99%.
  • Water -resistant and waterproof.  Water-resistant sunscreens protect your skin for 40 minutes, while waterproof sunscreens can protect your skin for up to 80 minutes.

References:

  1. http://www.aad.org/public/publications/pamphlets/sun_sunscreens.html