The sun giveth and the sun taketh away.
While the sun is the primary source of energy for all life, it’s kind of a two faced frenemy. Solar emissions consist of visible light and heat - very very important - and ultraviolet (UV) radiation - a little important but mostly pretty nasty.
It is this UV radiation that is responsible for superficial tanning, sunburn and on prolonged exposure - skin cancer. Skin cancer is the one of the most common types of cancer, and also one of the most easily preventable.
Just like visible light consists of the spectrum of colours that make up the rainbow (Is that the best colour in the world or what?), UV radiation consists of a spectrum of rays - UVA, UVB and UVC. These are classified on the basis of length, with UVC having the shortest wavelength and UVA having the longest wavelength.
Long story short, shorter wavelength UV rays are less able to penetrate the skin. UVC rays, in fact, are so lame, they can’t even get through the ozone layer.
UVB rays are the really tricky ones. They are the primary source of Vitamin D (yes, very very important) and also the primary source of sunburn.
UVA rays account for 95% of UV rays that penetrate the ozone layer. They cause skin aging, wrinkling and tanning. Over the last decade, there has been increasing amount of research that suggests UVA rays, by damaging cells in the epidermal layer of the skin, contribute to, and are possibly responsible for, initiating the development of skin cancer.
Broadly classified, there are two types of sunscreen - physical or chemical. Physical sunscreens are also called mineral sunscreens. Technically, all sunscreens contain some sort of chemicals so they are scientifically classified as inorganic and organic, but let’s go back a bit and keep it simple.
Physical sunscreens work by creating a physical barrier between the sun and you. They are mostly made of titanium or zinc based oxides.
Chemical sunscreens contain a bunch of complex sounding chemicals, but they work by absorbing the sun’s UV rays.
While there are bunch of other differences as well, my favourite sunscreen is zinc based physical sunscreen - it protects against the entire spectrum of UVA and UVB rays unlike titanium sunscreens, is less likely to irritate the skin as compared to chemical sunscreens and starts working its magic immediately after application.
If you’re on top of an 8000 m peak near the equator, at midday, do you need an SPF 10000 sunscreen? No, because they don’t exist, and that’s not how SPF works.
SPF does not indicate how ‘strong’ the sunscreen is. It is not a magic number. Bigger is not necessarily better. SPF is a comparative number that tells you how long it will take for your skin to burn when you use the sunscreen as compared to when you don’t use it. For example, while using an SPF 30 sunscreen, your skin will take 30 times longer to start turning red as compared to if you weren’t using sunscreen.
Most experts recommend SPF 30, and say anything above that is almost the same. It blocks 97% of the sun’s rays. If you’re spending a lot of time in intense heat, you can upgrade to SPF 50, which blocks 98% of the sun’s rays.
The secret to sunscreen use is actually liberal reapplication. Most users don’t reapply as frequently as they should, and they use much less than they should.
Reapply every two hours, and every one hour between 12 to 2 pm. Experts recommend a full tablespoon per application on your face and neck. 30 grams or three tablespoons for your full body.
Don’t let the clouds trick you into thinking you don’t need sunscreen, or you need less of it. UV rays penetrate cloud cover with little difficulty.
Going back to the experts (I know I sound like one, but I’m no scientist), a comprehensive approach to sun protection is much more important than using a bottle of sunscreen every day.
- Wear protective clothing and a broad-rimmed hat. These will protect you without leaving a greasy feeling on your face. A lot of outdoor apparel manufacturers make clothes that specifically protect against UV rays.
- Seek shade between the hours of 10 am and 4 pm. This is when the sun is strongest and causes the most damage, especially to those living near the equator. India is pretty close to the equator, in case you’re wondering.
- Pick a good pair of UV protection sunglasses. Protect your eyes, they’re extremely useful for seeing things. Use an appropriate category of lenses depending on the activity you’re engaging in.
- Be wary of reflective surfaces like snow. They can substantially increase the intensity of the sun’s rays.
- Use water-resistant, broad-spectrum sunscreen that protects against both UVA and UVB rays and doesn’t melt off when you sweat.
Don’t let this article scare you out of the outdoors. Stay safe, stay sunny, stay active.