When it comes to sun exposure you can find two strong opinions out there. First: avoid the sun as much as possible and protect yourself with SPF50+ sunscreen. Second: don't use sunscreen at all and don't fear the sun.
To form your own opinion it's good to have some knowledge about UV radiation, types of sunscreen and benefits & risks of the sun. In this article I want to share some of my research results with you to help you making informed decisions for your personal safe sun exposure.
UV radiation
The sunlight contains three different types of Ultraviolet radiation - UVA, UVB and UVC:
1. UVA - Ultraviolet A Rays
- Wavelength: long
- Penetration: deeper layers of the skin, ~95% reaching earth's surface
- Skin effects: tanning, responsible for skin ageing & wrinkling, DNA damage, enhance development of skin cancer
2. UVB - Ultraviolet B Rays
- Wavelength: medium
- Penetration: outer layers of the skin, mostly absorbed by ozone layer & atmosphere, ~5% reaching earth's surface
- Skin effects: responsible for sunburn, promote development of skin cancer
- Benefits: Vitamin D production
3. UVC - Ultraviolet C Rays
- Wavelength: short
- Penetration: absorbed by ozone layer & atmosphere
- Skin effects: most damaging - but as it's fully absorbed as it doesn't reach the earth's surface and is non of concern for the skin
UVA and UVB can be damaging for our skin but in different ways. UVB rays are more associated with sunburn and skin cancer, while UVA rays contribute more to premature aging and can also play a role in skin cancer development. To protect your skin from both type of rays, use a broad-spectrum sunscreen.
Types of sunscreens
There are two types of sunscreen which are designed to protect you from UV rays. They work in different ways and have different characteristics:
Physical sunscreens
- Active ingredients: zinc oxide and/or titanium dioxide (only harmful when inhaling)
- Protection:
- create a physical barrier on your skin to block and reflect UV rays
- provide immediate protection after applying
- Broad spectrum protection (UVA & UVB): yes
- Application:
- harder to blend
- can leave a white layer on the skin
Chemical sunscreens
- Active ingredients: carbon-based (Avobenzone, Octisalate, Octocrylene, Homosalate, Oxybenzone, Octinoxate, etc.)
- Protection:
- absorb UV rays and convert them into heat
- 20-30 minutes waiting period before ingredients are effective as sunscreen must be absorbed into the skin first
- Broad spectrum protection (UVA & UVB): not all of them, read the label carefully (need multiple active ingredients to protect against UVA & UVB)
- Application:
- easy to blend
- usually transparent after applying
Tips for safe sun exposure
- 10-20 minutes of sun exposure without sunscreen to stimulate vitamin D production
- Use sunscreen with UVA/UVB broad-spectrum protection
- Avoid sunburn
- Extra protection between 10 am & 4 pm when UV rays are strongest - sun hat, sun protecting clothing, seek shade
- After swimming, lots of sweating reapply
In a nutshell
Most important is to find a solution you feel comfortable with. I personally go the middle way. I don't avoid the sun completely as I think it has a lot of benefits like Vitamin D production. But I always keep in mind for how long I'll be exposed to the sun and at what time of the day.
I have a light skin tone and follow the rule no more than 20 minutes without sunscreen. During peak hours I stay in the shade or protect myself with clothes.
When it comes to sunscreen I personally stay away from chemical ones as they're full of nasty ingredients (active ingredients listed above, Parabens, Perfume, etc.). Instead I use mineral based sunscreen. And even here I have a close look in the ingredients list as some of them use bad ingredients, too.
