Safety in the sun: what do you need to know?

While spending time outdoors has many benefits, including reducing stress, providing options for being physically active and having access to vitamin D, exposing the skin to harmful sunlight. may increase the risk of skin cancer. Most types of skin cancer result from exposure to ultraviolet (UV) light, which can penetrate deep into the skin, damaging or killing skin cells. However, there are steps that can be taken to protect the skin from the damaging effects of the sun.

Reduce the risk

The most effective way to reduce the risk of skin damage and cancer is to minimize direct skin exposure to the sun:

• Clothing: Wearing clothing made from a densely woven fabric that covers the skin (such as long-sleeved tops) provides some protection against UV rays. Dark colored clothes are more effective because darker colors absorb more UV light than lighter shades, reducing the amount of UV light that can reach the skin.
• Hat: Wearing a wide-brimmed hat that protects the face, ears, and neck provides the best protection.
• Sunglasses: Sunglasses protect the thin and sensitive skin around the eyes, but also the eyes themselves. They can lessen the development of cataracts which can occur if the surface of the eye is burned. Reflected sunlight (by water or snow) is particularly dangerous to the eyes. Even while wearing sunglasses, one should avoid looking directly at the sun, as this can cause permanent damage to the eyes.
• Shadows: Avoiding direct sunlight by staying in the shade provides some protection from UV rays, but sunscreen and protective clothing should always be worn.
• Sunscreen: Generous application of sunscreen with a high sun protection factor (SPF) is important but should not be considered sufficient on its own. It is most effective when combined with other solar safety precautions. To be as effective as possible, it should be reapplied frequently and used before its expiration date.

Safety in the sun. Image Credit: kordeo / Shutterstock.com

What is the sun protection factor (SPF)?

The Sun Protection Factor (SPF) is a measure of the effectiveness of a given sunscreen agent and refers to the degree to which a product protects the skin from the harmful effects of ultraviolet (UV) light. UV radiation has a broad spectrum and is divided into different types of radiation, including UVA and UVB radiation. Exposure to UVA remains constant and has a cumulative effect over time, degrading elastin and collagen, and reducing elasticity.

UVB exposure is increased during the summer months and causes acute skin changes such as sunburn and pigmentation, but also chronic changes such as photocarcinogenesis. Photocarcinogenesis is the result of biochemical changes that lead to skin cancer.

SPF is a measure of the amount of UVB protection offered by a sunscreen product, measured by the amount of UVB it absorbs. In 2011, the United States Food and Drug Administration provided a clear formula for calculating SPF. SPF was defined as the dose of UVB required to produce a minimum dose of erythema (MED; the lowest dose of UV light needed to cause reddening of the skin) after application of a protective product. solar, divided by UV light causing MED on untreated skin.

When applied, this formula shows that an SPF of 15 correlates with 93% UVB absorption, an SPF of 30 is related to 96.7% absorption, and an SPF of 50 correlates with 98. % UVB absorption.

In the UK, products also receive a star rating which measures the degree of protection against UVA rays. Ranging from 0 to 5, the stars indicate the proportion of UVA absorbed by the product in relation to UVB. Since this system awards stars based on the UVA and UVB protection ratio (with 5 stars indicating that UVA and UVB protection is roughly the same), a product with a low SPF can be highly star rated.

Therefore, it is important to select a product with both a high FPS and a high star rating. A good level of sun protection is sunscreen with an SPF of 30 and a minimum of 4 stars.

How to apply sunscreen

Sunscreen should be applied liberally. If applied too thinly, it may not offer the claimed amount of SPF. It should be applied to all exposed skin areas, ideally twice: 30 minutes before sun exposure, and again before exposure.

It should be reapplied frequently, about every two hours, and immediately after swimming, showering, sweating, or towel drying, even if it is labeled as water resistant.

The best sun protection tips

• Protect skin with clothing, including hat, t-shirt, and sunglasses, and always choose sunscreen of at least SPF 30. Sunscreen should be applied liberally and frequently.
• Make sure you never let the skin burn.
• Spend time in the shade in the middle of the day when the sun is strongest.
• Be extra careful with children and keep babies and toddlers out of direct sunlight.

The references:

• Dale Wilson, B., Moon, S. and Armstrong, F. (2012). Comprehensive review of ultraviolet radiation and the current state of sunscreens. The Journal of Clinical and Aesthetic Dermatology, 5(9), 18-23.
• Latha, MS, Martis, J., Shobha, V., Sham Shinde, R., Bangera, S., Krishnankutty, B., Bellary, S., Varughese, S., Rao, P., & Naveen Kumar, BR (2013). Sun protection agents: a review. The Journal of Clinical and Aesthetic Dermatology, 6(1), 16-26.
• Ma, Y., & Yoo, J. (2021). History of sunscreen: an updated view. Journal of Cosmetic Dermatology, 20 (4), 1044-1049. https://doi.org/10.1111/jocd.14004
• Anon, (2019). Sun safety. [online] Available at: https://www.cdc.gov/cancer/skin/basic_info/sun-safety.htm.
• www.bad.org.uk. (nd). British Association of Dermatologists – Sunscreen Factsheet. [online] Available at: https://www.bad.org.uk/skin-cancer/sunscreen-fact-sheet.