What does first come to your mind when you go out on a bright sunny day? Obviously sun protection with high SPF. But do you know what the SPF value represents? Let’s find out.
It is commonly mistaken, higher SPF provides higher protection from UV rays. The fact is SPF 15 sunscreen blocks 93% of UVB radiation, just enough for most of the people. While SPF 30 blocks around 97%, and SPF 50 blocks 98%.
As American Academy of Dermatology President Dr. David M. Pariser told the New York Times, “As you get higher and higher, it’s not really a practical difference.” Naturally, the question comes to our mind, then why the numbers are so different? Because the companies calculate the SPF value by evaluating the times for a particular person to burn without sun protection and with sun protection. In simple words, if a person burns after 12 minutes of sunlight exposure then with SPF 15 he/she can sustain 15 times longer i.e. 3 hours. Although, this calculation actually works under control environment. In a real situation, sweat, friction, and different physical activities affect a lot which leads to shorter effectiveness. The dermatologist recommended method is to reapply sun protection once in every two hours.
So stay healthy and be protective.