Interview with Hong Kong Dermatologist John Yu on Sun Exposure and Protection

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2 min read

sun protection woman on beach

It’s summertime and what is more fun than spending a day out in the sun? Of course, the most important thing for anyone out basking in the sun is to safely protect their skin. Exposure to sunlight will not only give you a sun-kissed tan, but can also cause wrinkles and spots, and increase the risk of developing skin cancer. We interviewed Dermatologist John Yu to learn more about how to best protect our skin from harm while outdoors.


What effects does exposure to sunlight, and ultra-violet (UV) rays have on our skin?

Sunlight is the source of UV radiation that can cause free radicals to be formed on the skin and break down healthy skin cells. Overexposure to UV can cause increased pigmentation in the skin, damage the collagen of the skin and may lead to wrinkles and telangiectasia. UV radiation is also one of the leading factors responsible for skin cancer.

Does the climate affect our chances of obtaining skin cancer?

Yes, some regions, like the tropics, have climates that bring higher UV exposure, which leads to higher chances of developing skin cancer. Skin cancer is also more prevalent in areas where the ozone layer is damaged; the ozone layer is in fact one of the most important factors to blocking/absorbing UV radiation.

How can we ensure that we have an adequate level of sun protection?

If you can't avoid the sun, the best way to protect yourself from it (getting dark, burning) is to use physical sunblock and material sun protection such as umbrellas, hats, sunglasses, and long sleeves.

How important is sunscreen and how often should we wear it?

Sunscreen is important as it contains SPF (Sun Protection Factor) and can successfully limit the absorption of harmful UV rays by your skin. It is important to wear it daily, and apply it frequently throughout the day (every two hours or so) to ensure adequate protection. While UVB rays are lesser in the winter times, the level of UVA rays does not change. As UVA rays can still affect the healthiness of our skin, it is important to apply sunscreen during the wintertime also.

Does higher SPF sunscreen make a real difference?

While the difference between SPF 30 and 60 is minimal, it is important to wear moisturizers or lotions with an SPF of 15 and up. Be sure to pick a broad-spectrum sunscreen that protects against both UVA and UVB rays. The PA level (for UVA protection) of +++ is the best. My advice is to use a physical sunblock that contains zinc oxide to lessen the chance of an allergic reaction, while still providing good UVB and UVA protection.

What advice would you give to those who enjoy tanning, or who are frequently out in the sun?

Be very cautious of sun overexposure. Sunlight consists of UV rays that are responsible for reactions on your skin. Simply put, UVA rays contribute to skin aging while UVB rays contribute to skin burning.

How harmful are tanning beds and tanning lotions? Are they worse than sun damage?

Tanning beds can lead to skin cancer and they are worse than sun exposure as they give users a false sense of security that because their skin will not burn, it will not be bad for them. Tanning lotions such as fake tans are not harmful; it is just like wearing foundation/makeup on your skin!


Dr. John Yu is a Dermatologist practicing at his private clinic Dermacare Central. A graduate of University of Oxford, England, he has received training in dermatology at Johns Hopkins University Hospital, Baltimore, as well as specialist training in the Department of Health at the Queen Mary Hospital. He joined St. Teresa’s Hospital in 2007 as a consultant where he later set up the Skin and Laser Centre.

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This article was independently written by Healthy Matters and is not sponsored. It is informative only and not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be relied upon for specific medical advice.

Dr. Yu Ho Tak John Timothy
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