Top 10 Sunblock FAQs – How to Avoid Getting Burned

23 December 2008 By Kate Hubert

’Tis the season in the Caribbean and Down Under – white yachts, reflective water, blazing sun. It’s amazing how few crew and guests take the time to apply sunblock before working and playing on deck and in the water, even though most yachts keep vast quantities on board. Here are the 10 most Frequently Asked Questions about sunblock. The answers can help you prevent a nasty sunburn – or worse – for yourself and others on board.

1. Why use sunblock?
More reasons than you think:
- To prevent skin damage that can lead to skin cancer.
- To stop you from aging prematurely.
- Women taking the contraceptive pill are more susceptible to sun damage such as brown spots on their face.
- Sunburn is ugly, uncomfortable and can be dangerous.
- To help prevent sun allergies or prickly heat.

2. How should I apply sunblock?
Apply liberally at least 15-30 minutes before you go outside. Re-apply at least every two hours, especially after swimming or sweating.

3. What is a suntan?
When your skin produces the brown pigment melanin to absorb UV, blocking the skin from further damage. Sunburn does not turn into suntan – the red is caused by inflamed blood vessels, and is unconnected to the brown color produced by melanin after about two days.

4. Is there such a thing as a healthy tan?
A tan does protect you from further damage, but it is a sign that your skin is in trouble. Any tan must be built up slowly with no burning. You should still use a sunblock even if you’re tanned or naturally dark skin can and does burn. A little sun is good for you— it produces Vitamin D in the skin, without which you will be less able to absorb calcium. But lack of exposure to the sun is usually only a problem for dark-skinned people in countries with little sun.

5. What are UVA and UVB?
UVA (Ultraviolet A) is long-wave UV light, the kind found in black lights. UVB (Ultraviolet B) is medium-wave invisible light. UV lies at the extreme blue end of the scale; most of it is absorbed by our atmosphere.

6. How does the sun damage your skin?
UVB causes sunburn and direct DNA damage to the skin. Of every 1,000 photons of UVB that your skin’s DNA absorbs, one will cause some of the molecules of the DNA to fuse together so they cannot be copied correctly. This triggers sunburn and the production of melanin. UVA doesn’t cause visible symptoms such as sunburn, but it does make wrinkles and brown spots. Melanin and DNA can cope with UVA, converting it to harmless heat, but if UVA is absorbed by other molecules in the skin, it can release “free radicals” – which sever and mutate DNA strands, leading to problems such as cancer.

7. How do sunblocks work?
Sunscreens use chemicals that either absorb or reflect UV. The most common reflectors are zinc oxide and Titanium dioxide. (There have been some concerns about titanium dioxide, but it’s only been shown to be dangerous to lab rats if they breathe in large quantities of titanium dioxide dust...)

8. How do I choose the right sunblock?
- Pick an SPF of at least 15 for UVB protection.
- Look for the number of stars that tell you the UVA protection. (In the States you’ll have to read the small print....)
- Beware of the “once a day” sunblocks with chemical UV-absorbers that can leave yellow stains on everything – many yachts ban these.

9. What is SPF?
“Sun Protection Factor,” based on the protection you get against UVB only. An SPF of 10 means that you could stay in the sun 10 times longer while wearing it than if you were unprotected, i.e. if you normally burn in 15 minutes, it would take 150 minutes to burn wearing SPF 10. Dermatologists say that it’s best to use at least SPF 15, preferably SPF 30. For tan addicts – you will get a tan even if you’re using SPF 30 but you won’t burn. Even though it will take longer, it will last longer.

10. Do sunblocks stop skin cancer?
Most sunblocks block UVB and reduce your chances of getting squamous or basal cell carcinomas. There is conflicting information about the most deadly form of skin cancer – malignant melanoma. People who use sunblock do still get this disease – but this may be because they spend far more time in the sun. To prevent skin cancer, the best advice is to avoid the sun between 11 a.m. and 3 p.m., wear a hat, long-sleeved shirt and sunblock.