Sunscreen 
Sunscreen for Protection
What You Should Know about Sunscreen
Moderate amounts of Sun are great for snorkeling and relaxing, but too much sun will make your vacation miserable. One day of over-exposure can make your entire trip painful and uncomfortable. Further, allowing for excessive ultraviolet exposure can be very bad for your skin.
Ultra Violet Radiation and How It Affects Your Skin
There are two types of ultra violet radiation that affect you at the beach, UV-A and UV-B. UV-A, because of it’s wavelength, is not absorbed by the ozone layer, penetrates deeper, and ages your skin. UV-B is only partially blocked by the ozone layer and is responsible for burning your skin. If you can't remember the difference between UV-A and UV-B, think of the 'A' as standing for 'Aging' and the 'B' as standing for 'Burn'. Both cause skin cancer.
How Sunscreen Works
Sun shielding products fall into two general types. Absorbers, technically referred to as Sunscreens, are designed to soak up the UV rays and prevent them from reaching the skin. Reflectors, referred to as Sunblocks, bounce back or scatter UV rays away from the skin.
Absorbing and reflecting sunscreens are made with many different chemical compounds. Examples of absorbing ingredients are parasol and benzophenones. Examples of reflecting ingredients are zinc oxide and titanium dioxide. If your skin reacts badly to one, try another with a different chemical. Reflectors may be more suitable for sensitive skins.
How to Choose a Sunscreen
Sun Protection Factor – Sun Protection Factor, or SPF, is a measure of how effectively the sunscreen’s formula limits UV-B exposure and it is usually printed right on the front of the container. A sunscreen’s SPF number effectively means how much longer you can stay in the Sun compared to not wearing any sunscreen at all. In example, SPF 10 means you would be able to stay in the Sun 10 times longer, and SPF 15 means you would be able to stay 15 times longer. As an example, if you normally burn without sunscreen in 30 minutes, proper use of a SPF 15 sunblock would mean you could remain in the sun for 30 min x 15 = 450 minutes before burning.
Just to let you know, UV-B protection does not increase proportionally with the SPF number. For instance, an SPF of 30 does not offer twice the protection as an SPF of 15.
The Center for Disease Control and Prevention, The Environmental Protection Agency, and the American Cancer Society recommend an SPF of at least 15.
Broad Spectrum - If you’ve been reading carefully, you’ll notice that SPF indicates only UV-B protection, so it’s important you get a sunscreen labeled “Broad Spectrum”. Broad Spectrum sunscreens protect against both UV-A and UV-B exposure. They are both Sunscreens and Sunblocks
Waterproof – Ocean water and your bodies perspiration will wash sunscreen off your skin, so you will not have the same amount of protection you thought you had after swimming and tanning. Choose a waterproof sunscreen and this will help you to minimize constant re-application. Typically, water-resistant sunscreens will lose their SPF after about 40 minutes in the water; waterproof sunscreens will lose theirs after approximately 90 minutes. This varies brand to brand so remember to read your product's instructions and re-apply as needed.
Sensitive skin – if you have oily skin or are prone to acne, you should be using a water-based sunscreen. There are also sunscreens especially made for sensitive skin or your face.
Buy a brand that does not contain para-aminobenzoic acid (PABA) if you are konwn to be sensitive to that ingredient.
By the way, in the case of sunscreens, expensive sunscreens are not necessarily more effective than inexpensive ones.
How to Apply Sunscreen
Shake well. If left for long periods of time, the compounds in sunscreen are know to "clump together", and when applied will be providing you less protection.
Most people don’t put on enough sunscreen, so be sure to apply your sunscreen evenly and generously to your entire body. As a rule of thumb, use an ounce, roughly a handful.
Don’t forget your ears, back, shoulders, and the back of your knees and legs...especially if you are planning to snorkel!
Read your product label so you know when to reapply as dictated by your activity.
For Maximum Sun Protection
You should be applying your sunscreen at least 20 minutes before going outdoors, but 30 minutes is even better. Applying sunscreen early/ prior to your direct exposre will ensure that the sunscreen/ block is absorbed by the skin and is less likely to wash off when you perspire.
Sunscreens should not be your only means of Sun protection. Use natural protection as well. Trees and clothes, especially a hat and sunglasses. These are the perfect compliments to sunscreen.
Be aware of the expiration date on the bottle. The compounds that protect your skin will degrade over time and this will decrease the printed SPF rating that you are seeign on the front of the bottle.
Sun Exposure Facts
The Sun's Heat and it's brightness are not indicators of UV intensity. The damage to your body is being done by ultraviolet radiation that is not related to temperature. The Sun does not need to feel hot to damage your skin.
80% of the Sun’s of damaging UV rays can get through clouds.
60% of the day's sun-burning radiation occurs between the hours of 10 a.m. and 4 p.m.
Don’t confuse sunscreen, which protects against the sun's ultraviolet rays, with tanning lotions or oils, which mainly lubricate and create a shiny lather, ultimately enhancing the sun's rays.
According to the Oregon Health and Science University, Dermatology Department, children on average spend three times longer out in the Sun than adults, so be sure to re-apply sunscreen (to your kids and you) every two hours.
Another fact is that your typical summer fabrics will or provide a SPF of 6.5, less if the clothing gets wet.
