UV light, what is it?
UV stands for Ultra Violet and UV light is part of the electromagnetic spectrum that is radiated from the sun. Having shorter wavelength than visible light, all UV lights, including UVA, UVB and UVC, are invisible. These three UV lights differentiate from one another by their relative wavelengths, with UVA being the longest and UVC being the shortest.
While UVC is absorbed by the ozone layer and does not travel as far down the earth, UVA and UVB are our concern. UVA is a more immediate threat to your skin because with long wavelength and the ability to come through the clouds, it can affect your skin even on cloudy days. Even when you are inside a car driving, you will still be receiving radiation from UVA because this light can penetrate through the glass window and affect your skin.
UVA reaches the earth extensively and is primarily responsible for skin aging and the formation of fine lines. Even though being essential for the formation of vitamin D, UVA may also be responsible for the development of skin cancer by damaging keratinocytes. Interestingly, UVA is widely used in tanning technique with dose more intensified than that emitted from the sun. Conceptually, skin tanning is the process of shining UVA to the skin, which causes sustained damages to skin cells. Consequently, skin reacts by being darkened to prevent itself from further damage. This is why skin tanning is detrimental for your skin in the long run and you should take this fact into consideration before deciding to go with the flow.
Meanwhile, UVB can cause sunburn, cataracts, and initiate skin cancer.
Why is there skin cancer alert?
According to the American Cancer Society, every year in the U.S., more than 1 million cases of skin cancer are caused by UV light from the sun. The risk for getting cancer may come about from many factors. Overall, statistics and scientific evidence show that the following people would have higher risk of skin cancer:
- People with sensitive skin that gets burn easily,
- People with light skin, especially those having light colored eyes such as the Caucasians
- People staying outdoor frequently and for extended period of time
- People with skin defects such as freckles
- People from family with cancer tradition
How can I protect myself?
Get sunscreen. It provides just the protection you need. Use it frequently and repeatedly for immediate and long-term defense against the sun.
Limit exposure to the sun. If you could, try not to go out or do something outdoor from 10 am to 4 pm. It would be better if you can stay away from the sun for the most part of your day.
Cover yourself. Long sleeves, sunglasses, wide brimmed hat are needed when you have to face the sun.
What does that SPF mean?
SPF means Sun Protection Factor, which indicates the effectiveness of the sunscreen against UVB rays only. Currently, no rating exists against UVA. There exists a notion that the SPF number reflects the period of time a person using sunscreen can stay in the sun without getting sunburn as compared to the period of time a sunscreen-free person can. For example, applying SPF 30 would allow a person 30 times longer to get burn than without the sunscreen. No matter whether there is any truth in this definition, sunscreen is to be reapplied at least every two hours for extended outdoor activities, regardless of what SPF number you are using.
Higher SPF means better protection against UV rays. Theoretically, SPF 30 can absorb 97% of UVB rays while SPF 15 absorbs about 93%. In reality, however, the percent of absorption may vary depending on the specific locations on earth and the extent of exposure. SPF 30 is a common choice for usual sun block purpose at normal conditions and activities; SPF 40-50 may be used for extended exposure to the sun and winter activities, even though frequent reapplication is still needed.
How should I choose my sunscreen?
- Sunscreen that absorbs both UVA and UVB, known as “broad spectrum” sunscreen is the most common choice.
- If you are spending four hours and more outdoor, choose sunscreen with SPF of at least 30. Normally, SPF 30 is the best because it is effective, yet it is still moderate.
- Sunscreen is considered drug because of the active ingredients and thus is under the control of the Federal Drug Administration (FDA). Among the active ingredients recognized by FDA to be safe and effective are: Benzophenones, Zinc oxide, Titanium dioxide (or oxybenzone), Cinnamates (octinoxate or cinoxate), Salicylates. These active ingredients divert the impact of USV rays by absorbing, reflecting or scattering them.
- Because water interferes with the effectiveness of sunscreen, some products are intensified with water-resistant ingredients to increase the overall impact of sunscreen. Consider your skin’s needs, if you are so easily prone to perspiration or frequently in contact with water, you may want to go with water-proof sunscreen. Again, do not assume that because your sunscreen is water-resistant, you can stay protected for forever. Reapplication is needed at least every two hours.
- Paraaminobenzoic Acid (PABA in short) used to be an active ingredient in sunscreen products. But its use has been phased off due to allergy and other side effect reactions. You should make sure that your sunscreen is free of PABA.
How should I use my sunscreen?
- Sunscreen is needed whenever you spend extended time being outdoor, even though on cloudy days or in winter month, especially from 10 am to 4 pm.
- Apply sunscreen generously to all sun-exposed skin areas to give yourself enough protection at least 30 minutes before going out. This allows your skin to absorb the active ingredients. Pay attention to the most-neglected regions such as ears, face, hands, neck, and feet.
- Reapply sunscreen every two hours if you stay outside for an extended period of time, no matter what SPF number your sunscreen is or whether your sunscreen is water-resistant or not. In case there your skin becomes increasingly sweating, consider reapplying also.
- Even when using sunscreen, try not to stay out in the sun too long if you can. Find a shelter or seek shady place every now and then.
- If your skin is rubbed with a surface after the application of sunscreen, consider reapplying
- Do not forget to check the directions on your sunscreen tube and follow the instructions.
- Consult your doctor if you think your skin have special needs
What else should I need to know about sunscreen?
- Certain skin type more easily gets burned and thus needs extra protection. Caucasians with fair skin belong to this type and sunscreen is a must-have for their outdoor activities.
- The higher up you go, for instance on a mountain, the less protection you have by atmospheric gases against UV light. For every 1000 feet increment above the sea level, radiation from UV light increases by 4%. In addition, the closer you are to the equator, the more threat UV radiation is to you.
- The hotter and more humid, the less protection against UV light. Do not forget that sunscreen becomes less effective on your skin upon contact with water.