Kelly is a CRW member and a practicing Dermatologist
By Kelly O'Connor
Sun Protection
There’s nothing like New England biking in the summertime. July and August bring warmth and sunshine, but also a high amount of ultraviolet radiation (UVR)! Ultraviolet (UV) light from the sun induces DNA damage in skin cells that can eventually develop into cancer. The UV index tracks the hourly risk of UVR exposure by accounting for the amount of UVR passing through the ozone layer, forecasted cloud coverage, and altitude. It does not account for UVR that reflects off surfaces such as metal, snow, water, and pavement, which can add a lot of exposure on a road bike.
Sunscreen
The best way to protect sun-exposed skin is to wear sunscreen and there are three major headings you should look at on sunscreen labels. 1. Sun protective factor (SPF). SPF is the amount of UVR required to produce a sunburn on protected skin (with sunscreen) relative to the amount required on unprotected skin. A good rule of thumb is to use at least SPF 30, which protects against 97% of UV radiation and has been shown to decrease the rate of skin cancers. However, a well-designed study demonstrated that the “actual use” of SPF 100 prevented many fewer sunburns than SPF 50,1 so using a higher SPF is likely to be beneficial. 2. Active ingredients. There are two major types: physical and chemical blockers. Physical blockers, such as zinc oxide and titanium dioxide, are metal particles that sit on top of the skin and reflect the sun's rays. Chemical blockers, such as oxybenzone and octisalate, are absorbed by the top layer of the skin and absorb UVR. Physical blockers are broader in UV spectrum coverage, immediately effective, safer for the environment, and better for people with sensitive skin. Many older physical sunscreens left a white cast on the skin, but newer formulations rub on much more clearly. 3. Water resistance. If a sunscreen has been tested for water resistance, it is effective for either 40 or 80 minutes during swimming or sweating. So whether you are climbing up hills on the Mighty Squirrel ride or pulling your group up Nantasket beach, reach for a sunscreen with 80 minutes of water resistance.
Kind in mind there are many different formulations of sunscreen: lotion, sprays, sticks, balms, powder. While a lotion makes a nice initial coat before your ride, a stick that fits into your back pocket makes reapplication less messy. Try out different ones and figure out which ones work best for you. At the end of the day, the best sunscreen is one that you will actually put on.
Don't want to douse yourself in sunscreen every time you ride? Try sun protective clothing like long sleeve riding shirts, gloves, skull caps, ear covers, and long socks. You don’t need to spend a fortune on specific SPF 50+ approved clothing- stretch out your clothing and hold it up to the sun. If light does not pass through it (and you don’t squint), then the fabric weave is tight enough to provide protection.
Adjuncts to Sunscreen
1. Topical vitamin C and E serums. These have been shown to increase resistance to UVR and decrease the amount of DNA damage to skin cells.2 I recommend applying a vitamin C and E serum in the morning, 10-15 minutes before sunscreen. 2. Oral Polypodium leucotomos. This is extracted from a tropical fern and made into a capsule. Studies have shown that people who took two 240 mg capsules daily had less sunsburns compared to those taking a placebo, 3 and that there were fewer mutations on a molecular level.4 Vitamin D Sunlight converts a precursor of vitamin D in the skin into a more active form, which regulates calcium levels (keeping bones strong). Despite this fact, everyday sunscreen use has not been found to lead to vitamin D deficiency. Moreover, the most efficient way to get vitamin D is through the diet. Fatty fish, fish liver oils, and fortified foods (milk, cereal, mushrooms) are among the best sources. If you are concerned that you are not consuming enough vitamin D in your diet, I recommend taking 2000 IU of vitamin D daily. Ride safe and protect yourself from the sun!
Kelly O’Connor, MD, FAAD Medical, Surgical, and Cosmetic Dermatologist South Shore Skin Center in Norwell, MA
References:
1. Williams JD, Maitra P, Atillasoy E, Wu MM, Farberg AS, Rigel DS. SPF 100+ sunscreen is more protective against sunburn than SPF 50+ in actual use: Results of a randomized, double-blind, split-face, natural sunlight exposure clinical trial. J Am Acad Dermatol. 2018 May;78(5):902-910.e2. doi: 10.1016/j.jaad.2017.12.062. Epub 2017 Dec 29. PMID: 29291958.
2. Murray JC, Burch JA, Streilein RD, Iannacchione MA, Hall RP, Pinnell SR. A topical antioxidant solution containing vitamins C and E stabilized by ferulic acid provides protection for human skin against damage caused by ultraviolet irradiation. J Am Acad Dermatol. 2008 Sep;59(3):418-25. doi: 10.1016/j.jaad.2008.05.004. Epub 2008 Jul 7. PMID: 18603326.
3. Nestor MS, Berman B, Swenson N. Safety and Efficacy of Oral Polypodium leucotomos Extract in Healthy Adult Subjects. J Clin Aesthet Dermatol. 2015 Feb;8(2):19-23. PMID: 25741399; PMCID: PMC4345929.
4. Mohammad TF, Kohli I, Nicholson CL, Treyger G, Chaowattanapanit S, Nahhas AF, Braunberger TL, Lim HW, Hamzavi IH. Oral Polypodium Leucotomos Extract and Its Impact on Visible Light-Induced Pigmentation in Human Subjects. J Drugs Dermatol. 2019 Dec 1;18(12):1198-1203. PMID: 31859468.
