How the Sun Influences Skin Health and Aging

Table of Contents

1. The Effects Of Sun Exposure On The Skin
2. The Risks Of Skin Cancer From The Sun
3. The Sun And Premature Aging (Photoaging)
4. How To Protect Your Skin From The Sun
5. Common Myths And Misconceptions Around Sun and Skin Health
6. Conclusion
7. References

Everyone likes being out in the sun, and for good reason. The sun has a wide range of both physiological and psychological benefits such as stimulating the production of vitamin D [1] which is essential for bone health and immune function, boosting serotonin levels [2] which can improve your mood and encouraging social interaction through outdoor activities and gatherings. There are many other benefits to enjoying the sun’s rays, but unfortunately the sun can also be harmful to both your health and skin, so it’s important to take precautions to reduce your risks to sun exposure. This article looks at the different ways the sun can impact your health and your skin, how to protect yourself and mitigate these risks, and we’ll also debunk some common myths around sun exposure and tanning.

The Effects Of Sun Exposure On The Skin

The sun emits ultraviolet (UV) radiation that can be classified into three different types: UVA, UVB and UVC rays. UVA rays have a longer wavelength and can penetrate more deeply into the skin, causing wrinkles, loss of elasticity in the skin and other signs of premature aging. UVB rays have a shorter wavelength and are the main cause of sunburn. Both can cause tanning which is the skin’s defence mechanism to prevent further damage by producing more melanin, a natural skin pigment.

The sun also emmits UVC rays which have the shortest wavelength and the highest energy making them the most dangerous, however these are blocked by the ozone layer around the Earth so aren’t usually considered a risk, but they can be found in some man-made sources like mercury lamps.

The Risks Of Skin Cancer From The Sun

Although there are a number of risks associated with sun exposure, the most well-known and often most dangerous is skin cancer. Both UVA and UVB rays can contribute to the development of skin cancer, but UVB rays are more strongly associated to this [3]. This is because the radiation can damage the DNA in skin cells, potentially leading to mutations which can cause skin cancer [4]. The most common types of skin cancer associated with sun exposure are basal cell carcinoma, squamous cell carcinoma and melanoma.

The Sun And Premature Aging (Photoaging)

Whilst cancer is generally considered the biggest risk from sun exposure, premature aging, also known as photoaging, is another important factor to consider. Both UVA and UVB rays can cause this effect, however as the UVA rays penetrate deeper into the skin, they are primarily responsible. Here are some ways the sun can cause premature aging:

Collagen breakdown

When exposed to UV radiation, the production of enzymes is triggered and these break down collagen and elastin, proteins that are responsible for the skin’s firmness and elasticity. As these proteins break down, the skin starts to sag and can become wrinkly.

Changes in pigmentation

As mentioned earlier, UV rays trigger the production of melanin as a defence mechanism for your skin, resulting in a tan. However, excessive and prolonged exposure to the sun can lead to uneven melanin production, resulting in dark spots and an uneven skin tone.

How To Protect Your Skin From The Sun

Given the risks associated with exposure to the sun, it’s important to stay protected and protect your skin. There are few ways you can do this:

Use an appropiate sunscreen

Sunscreens contain active ingredients to help absorb, reflect and scatter UV radiation [5]. These are classified into two main categories: chemical (organic) filters and physical (inorganic) filters. Chemical filters such as avobenzone and oxybenzone help to absorb and dissipate UV radiation, protecting the skin from potential DNA damage by preventing it from penetrating the skin. Physical filters such as zinc oxide and titanium dioxide help to block UV rays, reflecting the radiation away. Antioxidants such as vitamin C and vitamin E are often included as well to help neutralize free radicals and prevent cellular damage.

When purchasing a sunscreen for your skin, look at the SPF rating which refers to how much UVB radiation is blocked (SPF does not apply to UVA rays). An SPF of 30 is usually considered sufficient for most, blocking 97% of UVB radiation compared to SPF 15 which blocks just 93%. However, increasing beyond SPF 30 has smaller benefits, with SPF 50 blocking just 98% and SPF 100 blocking 99%. In addition to SPF rating, sunscreens also provide a star rating out of 5, indicating the amount of protection for UVA radiation. 5 stars is the most effective, and the lowest recommended rating is 4 stars.

Wear protective clothing

In addition to sunscreen, it’s important to prevent too much sun exposure by wearing clothing such as hats and sunglasses and seeking shade where possible.

Common Myths And Misconceptions Around Sun and Skin Health

You can’t burn on a cloudy day

Due to the shade offered by clouds, it’s often believed that you don’t need protection from the sun. However, UV rays are able to penetrate clouds and so it’s important to still wear sunscreen and protective clothing.

Tanning protects you from sunburns

Some people may decide to tan before going away on holiday somewhere sunny in order to protect themselves from burning, however experts believe that a tan is equivalent to wearing a sunscreen with an SPF of about 3-4 [6], compared to the recommended SPF 30. This means that a tan will do little to prevent burning and prevent the aforementioned risks.

Dark skin doesn’t need protection

Although people with darker skin tones are less likely to burn, there is still a risk of burning or developing skin cancer so it’s important to wear sunscreen and stay protected.

UV rays are strongest when it’s hottest

This isn’t necessarily true, as UV rays aren’t actually hot and you can’t feel them, instead the heat from the sun actually comes from infrared radiation. UV rays are strongest when the sun is highest in the sky, and you can see when the UV rays are strongest at the Met Office here.

Aftersun products will repair damage caused by the sun

This isn’t true unfortunately. Whilst they can soothe your skin and make you feel better, any damage caused to your DNA from sunburn will not be repaired by aftersun products.

More expensive sunscreen is better

This is seldom the case, and the two important factors to look at when buying a sunscreen are the SPF rating and the star rating. Sunscreens are tightly regulated in the U.K., and if these ratings are high it should offer great protection depiste being a lower cost than some premium brands.

You can’t burn through glass

If you’re sitting in your car or conservatory thinking you’re protected, this is sadly not the case. Whilst UVB rays are largely blocked by glass, UVA rays can pass through and still damage your skin, so sunscreen and protection is important.

Conclusion

Hopefully after reading this article you have a better idea of how the sun can impact your skin and the importance of protecting yourself from the sun's rays. Both UVA and UVB rays can damage your skin and cause certain types of skin cancer, so protection is very important, particularly when these rays are at their strongest. A good sunscreen with a high SPF rating and star rating offers great protection when applied frequently, but shade is the best way to protect yourself where possible. This will help reduce your risk of skin cancer and mitigate the damage of photoaging, allowing you to maintain healthy and youthful skin.

References

[1] Kim, H.-L. (2023). Anti-Inflammatory Effect of Vitamin D via Suppression of YKL-40 Production: One of the Possible Mechanisms for Cardiovascular Protection. Korean Circulation Journal, [online] 53(2), pp.103–105. doi:https://doi.org/10.4070/kcj.2023.0016.  ‌

[2] Mead, M.N. (2008). Benefits of Sunlight: A Bright Spot for Human Health. Environmental Health Perspectives, [online] 116(4), pp.A160–A167. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2290997/.

[3] Glanz, K. (2011). Skin Cancer Prevention. Fundamentals of Cancer Prevention.

[4] Rhee, H. J. van der, Esther Vries, Claudia P. Coomans, Pieter van de Velde and Jan Willem Coebergh. “Sunlight: For Better or For Worse? A Review of Positive and Negative Effects of Sun Exposure.” (2016).

[5] Henderson, Stuart, Kerryn King, Ken Karipidis, Rick Tinker, and Adele Green. 2022. “Effectiveness, Compliance and Application of Sunscreen for Solar Ultraviolet Radiation Protection in Australia.” Public Health Research & Practice 32 (1). https://doi.org/10.17061/phrp3212205.

[6] H, Robert. 2017. “The Problem with Tanning (and the Myth of the Base Tan) - Harvard Health Blog.” Harvard Health Blog. March 30, 2017. https://www.health.harvard.edu/blog/problem-tanning-myth-base-tan-2017041211528.