Why Should You Wear Sunscreen Daily, Outdoors & Indoors?

 If you live in a tropical country, you've most likely heard that you ought to stay out of the sun as much as you can to not get sunburnt. Yet for some reason, most of us go about our daily activities without any sunscreen on.  

Why is that? Hopefully, this article can help you to see the importance of sunscreen and why we should incorporate it into our daily routine. Trust me, we all need it- no matter our complexion, ethnicity, whether we're indoors or outdoors, in rain or sunshine, etc. 

Let's get to it 👇

As you may or may not know, the sun brings with it Ultra-Violet Radiation (UVR). It is the very reason we are encouraged to limit sun exposure, to begin with. UVR is a non-ionizing form of radiation that the sun emits. It comes in 3  types based on wavelength measurements and in descending order, the types are UVA, UVB, & UVC. 

UVC is absorbed by the atmosphere and the ozone layer entirely so it does not get to the earth's surface. UVB is mostly absorbed by the ozone layer but some of it does reach the earth, and UVA is not absorbed by the ozone layer and therefore reaches the earth's surface fully. Both UVA and UVB radiation are known to affect human health and increase the risk of skin cancer. However, UVA mainly contributes to the aging of the skin and penetrates deeper into the skin than UVB, and UVB is primarily responsible for sunburns (Figure 1). 

Figure 1: Type of UVR, Absorption Level & Associated Risks

So, we know what UVR is and we know the types of UV radiation that reach the earth, UVA and UVB. How do we measure this radiation? 

Ultraviolet Radiation is measured using the UV Index. It is a tool that is used in informing the public about the intensity of UV radiation on a daily basis and gives the population an indication as to how much they should be reducing their exposure to this solar radiation, based on its intensity. It is important to note that UVR levels fluctuate throughout the day but the UV Index gives a general prediction of the level at noon. 

According to the US Environmental Protection Agency (US EPA), the Global Solar UV Index ranges as follows (Figure 2):

Figure 2: Global UV Index & Protective Measures

Where there is a UV index of about 0-2, the WHO says that persons can enjoy being outdoors safely, from 3-7, it is worth finding shade, especially during midday, and wearing protective clothing that does not expose a lot of your skin to the sun's rays. Sunscreen should be utilized! Where the UV index is 8+, the WHO encourages people to avoid being outside as much as possible, seek shade, and wear sunscreen, protective clothing, and hats if outside. 

In the tropics, the UV index is usually higher than in other climates since the sun's intensity is significantly stronger in these areas. On a typically sunny and even cloudy day in Trinidad (and the rest of the tropics), it is unsurprising to find that the UV index may be above 8. Hence, if you live in the tropics, please ensure that you take precautions at all times while limiting your exposure to the sun, for your own health benefit. 

In other, more temperate regions, the UV index is generally lowest in winter and highest in spring & summer. Regardless, you should always ensure that you limit exposure and stay prepared with your sunscreen on. 

You may be thinking, 'Okay, I understand the importance of wearing sunscreen while I am outdoors, but why is it important to wear it indoors?'

Hang on, we're getting there! 

Homes and buildings usually have windows. UVB radiation is blocked by the glass in the window and is not able to penetrate it to reach your skin. On the other hand, UVA can. Remember, UVA is responsible primarily for skin aging. If we do not protect our skin indoors by wearing sunscreen and protective clothing (especially in well-lit areas near windows or when intermittently being exposed to sunlight e.g. doing chores), UVA radiation penetrating the glass is likely to cause premature skin aging over time. 

What can we use to help us protect ourselves? Sunscreen, of course!

Sunscreen is a photoprotective product applied to the skin that either absorbs the UVR (chemical sunscreens) or reflects the sun's UVR (mineral sunscreens) and helps to protect your skin from sun damage. It contains Sun Protection Factor (SPF) which indicates how well the sunscreen protects the skin from sun damage. A broad-spectrum sunscreen of SPF 30+ is recommended for all people. It should be reapplied to the skin every 2 hours. Without it, you are at an increased risk of developing health conditions like skin cancer, premature aging, etc. 

Figure 3 shows some of the benefits of wearing sunscreen:

Figure 3: Benefits of Using Sunscreen

Summary:

• The sun emits UVA, UVB, and UVC radiation.
• UVA & UVB reaches the earth with UVA mainly causing skin aging and UVB is primarily responsible for sunburns. They both can increase the risk of skin cancer.
• The UV Index is an indication of the intensity of the UVR on a particular day and is used to help people plan better to protect themselves from sun damage.
• According to the US EPA, 0-2 on the UV index is considered low, 3-5 is moderate, 6-7 is high, 8-10 is very high and 11+ is considered extreme. 
• Tropical climates generally have higher UV indices and UV intensities and so extra precautions should be taken to limit sun exposure in these areas. 
• UVA penetrates the skin deeper than UVB and UVA can also penetrate glass, which is why we should be wearing sunscreen indoors, especially when exposed to natural light.
• Sunscreen is a photoprotective skin product that can reflect or absorb UVR, it contains SPF that tells us how well the sunscreen protects against skin damage and should be reapplied every couple of hours. 
• Broad-spectrum sunscreens with an SPF of 30+ are recommended. 
• Sunscreen should be applied every single day regardless of the weather conditions and based on the UV index, both indoors and outdoors. 

And that's it! It's my hope that you understand why it's super important for you to wear your sunscreen to protect your skin against sun damage.
Next time you head out, remember to pick up some quality sunscreen for yourself - you deserve it! 😊

Hey there! Hope you learned something new from this 😊

If you've got any questions - leave me a comment & I'll get back to you as soon as I can!

Until next time, stay safe & ambitious - TCB 💛

REFERENCES

CDC. 2021. “UV Radiation.” Centers for Disease Control and Prevention. June 28, 2021. https://www.cdc.gov/nceh/features/uv-radiation-safety/index.html.

EHE Health. 2020. “TOP 5 IMPORTANT REASONS YOU SHOULD ALWAYS WEAR SUNSCREEN.” EHE Health. December 2020. https://ehe.health/blog/always-wear-sunscreen/.

Johns Hopkins Medicine. 2021. “Sunscreen and Your Morning Routine.” Hopkinsmedicine.org. August 8, 2021. https://www.hopkinsmedicine.org/health/wellness-and-prevention/sunscreen-and-your-morning-routine.

Mahoney Dermatology. 2021. “5 Important Reasons to Wear Sunscreen Daily.” Mahoney Dermatology. February 25, 2021. https://mahoneydermatology.com/5-important-reasons-to-wear-sunscreen-daily/.

Stump, Scott. 2021. “Do You Need to Wear Sunscreen Indoors?” Today.com. TODAY. August 9, 2021. https://www.today.com/health/do-you-need-wear-sunscreen-indoors-t227716.

United States Environmental Protection Agency. 2004. “A Guide to the UV Index.” Epa.gov. https://www.epa.gov/sites/default/files/documents/uviguide.pdf.

University of Washington. 2021. “Wear Sunscreen Daily.” Right as Rain by UW Medicine. RightAsRain. July 14, 2021. https://rightasrain.uwmedicine.org/well/prevention/sunscreen.

World Health Organization. 2022. “Radiation: The Ultraviolet (UV) Index.” Who.int. 2022. https://www.who.int/news-room/questions-and-answers/item/radiation-the-ultraviolet-(uv)-index.