Every time the summer is near becomes a great opportunity to learn why is it important to protect your skin from sun damage, even though sunscreen should be applied 365 days a year. Science is increasingly showing that the ultraviolet rays emanating from the sun cause considerable damage to the skin. In fact, data from the World Health Organization reveal that every year there are between 2 and 3 million cases of skin cancer, which means that one out of every three cancers diagnosed are skin cancer.
For those very reasons it is so important to wear sunscreen on a daily basis, but everyone talks about “getting a sunscreen with SPF 30 or 50″. What the heck does that mean??
How Did the Famous SPF Came to Life?
SPF stands for Sun Protection Factor, a legend that we commonly see on sunscreen packaging. The history of sun protection began in 1938 when Franz Greiter, a chemistry student, suffered from sunstroke while mountaineering on his climb to the Piz Buin summit in Switzerland. This inspired him to develop one of the world’s first sunscreen products in 1946, which he called Piz Buin Glacier Cream.
He created this cream in collaboration with his wife, Marga, an expert beautician, and gradually developed a specialized sun care brand to develop cutting-edge sun protection products. In 1962, Greiter introduced the sun protection factor (SPF), the world standard level for determining the effectiveness of sunscreen when applied to the skin.
Thus, Dr. Greiter based the SPF calculation on a sunburn and it is determined mainly by how long we can remain exposed without getting pink skin (one of the first signs of sunburn).
How to Choose a Good SPF in a Sunscreen?
We already understood that SPF was created because it refers to the time our skin will be protected before sun damage occurs, but this doesn’t mean that if you buy a cream that says 30 SPF it will only protect you for 30 minutes. In reality, that number should be multiplied by the number of minutes it takes for your skin to turn red when you go out in the sun, and that obviously varies a lot between skin types and skin tones. WHAAAAT?!
Example: If you have pale skin, it is estimated that it takes only 5 minutes for it to start turning pink. So if you apply a 30 SPF sunscreen, you multiply the five minutes it takes for your skin to burn by the factor 30, which means you will be protected for 150 minutes. If you buy a 50 SPF sunscreen, you will be protected from the sun’s radiation for 250 minutes.
So, when you intend to buy sunscreen, take a SMALL test before you invest your money. Go out on a sunny day with a stopwatch and a mirror in hand. Start the timer from the first moment you’re outside and stop it when you start feeling your skin pink or very hot. That’s the time you should multiply the SPF by and the time you should reapply your sunscreen.
The formula in a nutshell is:
SPF x Number of minutes you start noticing your skin getting hot = How long your sunscreen lasts.
So next time you buy a sunscreen, think about how long it will protect you from sunburn and how often you will need to reapply it.
This story was originally published in Spanish by Daniela Bosch in Cultura Colectiva.
