SUNSCREENS: The WHAT & WHY plus the importance of REAPPLYING

WHAT is sunscreen?

Sunscreen is a topical cream that contains ingredients that either absorb or reflect UV light coming from the sun. Octyl methoxycinnamate, for instance, is a chemical contained in some sunscreens that attracts or absorbs UV rays. Zinc oxide and titanium dioxide are found in many creams and reflect sunlight away from the skin.

Either way, sunscreens can be effective in helping to keep your skin from burning. If you are in the sun for any length of time, however, the effectiveness of a sun product (even if it has a high SPF) will be diminished. Why? Creams are no match for the power of the sun. Remember, SPF refers to burn time, not freedom from all sun damage.

Sunblock, by the way, is essentially the same thing as sunscreen, but it sounds like it totally blocks out the sun, doesn’t it? It doesn’t! It’s just another name for the same thing. Sunscreens and sunblocks are both helping to protect your skin when out in the sun, but both are only filtering UV rays. Both are keeping your skin from burning. So although a cream says it’s a sunblock, nothing totally blocks the sun except being inside.

I have used this example before, but I want to include it again for emphasis. If given a choice between wearing sunscreen on my face without a hat or a hat with no sunscreen, I would always choose wearing a hat with no sunscreen. UV rays can penetrate through glass, clouds, and water. Why wouldn’t they be able to cut right through a thin layer of cream on the skin? Obviously the optimum defense would be to wear both a hat and sunscreen, but I think you get the picture.

WHY wear sunscreen?

Sun exposure is cumulative. This means that throughout your lifetime—from birth—you are accumulating what I call “sun time,” which is simply any sun exposure, whether at the beach or to and from your car, every day of your life. Therefore, for the long-term health of your skin, you want to limit the amount of sun damage (over exposure and especially unprotected exposure) you incur over your lifetime. Sunscreen is one important way to do this.

Sunscreen helps to absorb or reflect damaging rays from the sun, allowing you to stay outside longer without burning. Sunscreen, because it does help filter out sun rays, can help to postpone the threat of skin cancer. Sunscreen does not prevent cancer, but it can help your skin defend itself from the harmful rays of the sun.

If you tend to get dark spots on your face, watch out—sun exposure increases the already dark color of this hyperpigmentation. Any amount of sunlight will do this. Just innocently walking to and from your car every day can darken these spots. If you are prone to hyperpigmentation, wearing sunscreen all the time is vitally important. Otherwise these dark, sometimes large pigmentation spots can take over your face.

As many of you have heard me say, I am a big believer in wearing hats to keep direct sunlight off your face. Wearing sunscreen is also an important component in helping to keep sun rays from penetrating deep into your tissues and therefore for the long-term health of your skin. In short: wear sunscreen! 

The importance of REAPPLYING sunscreen.

I was talking with a client one day about using sunscreen. I was explaining about the need to reapply, especially if you are exercising. I went on to say that I especially needed to do this since I always wipe my face once I start sweating, which no doubt takes just about all the sunscreen away too. She said she didn’t wipe, which was kind of a revelation to me. You mean some people don’t feel the need to wipe the dripping sweat off their faces? 

If you are like me and you do wipe the sweat off your face, know that an appreciable amount of any sunscreen you have applied to your face (or wherever) is coming off during the wiping process. 

One day in Colorado I was running a trail, and it was hot. I wiped and wiped and keep internally commenting on the fact that basically my face was left sunscreenless—although I did (and always do) have a hat on. Did I reapply my sunscreen? No. Do you in that situation? Since realistically I wasn’t going to stop my run to reapply sunscreen, I just knew that I would be getting sun exposure with little or no sun protection by the end of that run. Obviously you could reapply at any point if you took a break to catch your breath or to take in the beauty of wherever you are (for me it was the iconic Colorado foothills). 

The moral of this story is: Reapply your sunscreen! And if you can’t or don’t, just be aware you are putting in clock-time for UV radiation. Usually you’ll be able to reapply if you’re more stationary (like at the beach or on a boat). But if you’re out exercising and unable to reapply, hopefully you enjoyed your outdoor activity, regardless.

As I mention in almost any article on sun protection, please—if you haven’t already—see a dermatologist for a full-body mole check. It’s a good idea to do this annually.

For more information, see:

• How to use sunscreen
• Top 10 reasons for not wearing sunscreen: What’s your excuse?
• NO SWEAT: What happens when sweat dries on your skin?

Optimally, wear both sunscreen and a hat