The Importance of Sun Protection

As the weather starts to warm up, many Southern Utahans are looking forward to getting outside and enjoying themselves. This is particularly true after diligently socially distancing for over a year now. The benefits of natural sunlight of Vitamin D synthesis and improved mood are well known. Unfortunately, the potential damage from natural light is also well know. Ultraviolet (UV) B rays are responsible for sunburn, inflammation, hyperpigmentation (deepening of skin tone, freckling), and photocarcinogenesis (the formation of cancer from sunlight). UVA rays also contribute to photoaging, hyperpigmentation, and may be involved in carcinogenesis.

Thankfully, there are several easy strategies we can use to combat the damage caused by UVA and UVB radiation while still enjoying the great outdoors and its benefits. Photoprotection includes regular use of sunscreens, sun avoidance during peak hours, and sun-protective clothing.

Sunscreens are topical preparations, often creams or aerosolized sprays, containing substances that reflect and scatter or absorb UV radiation before it can absorb into the skin. Broad-spectrum products with a sun protection factor (SPF) of 30 or greater are recommended. Possibly more important than the SPF though, is proper application of sunscreen. These must be applied in liberal amounts, repeatedly, to all sun-exposed parts of the skin to provide effective protection. What is a “liberal” amount? In general, an average-sized adult will need to apply enough sunscreen to fill a 1oz or 30 mL shot glass, or 6 teaspoons!

Most people simply do not apply enough sunscreen or do not reapply it frequently enough to really get the protection they think they’re getting. To put that into perspective, using half the suggested amount only gives one third of the protection advertised on the bottle. Many health care providers suggest an average-sized adult apply approximately 1 teaspoon to the face/neck area, 1 teaspoon each to the front and back of the torso, 1 teaspoon for each upper limb, and 2 teaspoons for each lower limb. Sunscreens should be applied 15 – 30 minutes before sun exposure, a few minutes (ideally 10 – 20) before dressing, and then reapplied every two hours. Even sunscreens which are labeled as “water resistant” need to be reapplied as the labeled SPF is only “there” for about 40 minutes in water or with heavy sweating. Sunscreens that are labeled as “very water resistant” need to be reapplied after 80 minutes of activity in water or with heavy sweating.

Selecting a sunscreen with a combination of inorganic (mineral) and organic filters provided optimal protection. Common mineral filters include titanium dioxide and zinc oxide. These minerals are very safe and most do not get absorbed past the deepest layer of the epidermis, the stratum corneum, meaning they do not get absorbed into your “system”. For the extremely diligent among you, some common organic filters include: Avobenzone, Oxybenzone, Octocrylene, and ecamsule. These ingredients are also absorbed in only very minimal quantities, but for those who are concerned about this, sunscreens with mineral filters are recommended. If you want a sunscreen that’s coral reef safe, mineral filters which have particle sizes in the micro (or non-nano) realm are best. To stay reef safe, stay away from: Oxybenzone, Octinoxate, Octocrylene, Homosalate, 4-methylbenzylidene camphor, PABA, Parabens, Triclosan, any nanoparticles or “nano-sized” zinc or titanium (if it doesn’t explicitly say “micro-sized” or “non-nano” and it can rub in, it’s probably nano-sized), any form of microplastic such as “exfoliating beads”.

Nearly half of UV radiation is received between 10 a.m. and 4 p.m., when the sun’s rays are the strongest. Completely avoiding sun exposure during these hours might not be reasonable for summertime merry making, but it’s something to keep in mind. Sun-protective clothing is often more feasible than peak hour avoidance. The degree of protection provided by clothes is called the ultraviolet protection factor, or UPF. In general, fabrics which are a tighter weave, darker in color, not heavily worn or faded, and relatively less stretchy tend to offer better UPF. Additionally, some fabrics are treated with UV-absorbing chemicals which increase their UPF. The tightness of the weave is generally thought to offer more protection than other factors. It is also possible that washing a garment with detergents containing optical whitening agents might increase the UPF. Categories are UPF 15 – 24 for good protection, 25 – 29 for very good, and 40 – 50 for excellent protection.