Summer Safety Part 2: Sunscreen

Jul 18, 2020

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By Dr. Angela M. Meyer, MD, FACP, Health Professionals of Winfield

The staff at Health Professionals of Winfield hopes you are enjoying your summer and the great outdoors. Here are a few common questions/patient issues we encounter this time of year regarding sunscreen.

What does sunscreen protect against? UV radiation is capable of injuring the skin. UVA has a shorter wavelength and makes up most of the terrestrial radiation. It remains constant throughout the day and year. It causes long-term skin damage. UVB is largely responsible for sunburn. UVB is strongest at midday. Both can cause photoaging and skin cancer.

What does SPF mean? Sun Protection Factor (SPF) is the ratio of the time required to develop a minimally detectable sunburn while wearing a sunscreen product to the time required without wearing the product. When properly applied, an SPF 15 sunscreen allows penetration of 1/15th (7%) of UV photons.

How much sunscreen needs to be applied? For maximum efficacy, sunscreen should be applied about 15-30 minutes before sun exposure and reapplied at least every two hours and after swimming or sweating. Water-resistant sunscreens remain effective for 40 or 80 minutes while swimming or sweating; no sunscreens are waterproof. For maximum effect, approximately one teaspoon of sunscreen should be applied to the face and neck and one to each arm; two teaspoons should be applied to the torso and two to each leg. For example, a 4 ounce container of sunscreen only provides 2-4 whole body applications of an adult.

I am deficient in Vitamin D, should I wear sunscreen? The answer is yes. Only 2-8 minutes of unprotected summer sun is required by most people to maximize synthesis of Vitamin D3. It is not clear if sunscreen use leads to a vitamin D3 deficiency.

Can I use sunscreen on my baby? Sunscreen use is generally recommended for children >6 months old during any sun exposure that might burn unprotected skin. Inorganic sunscreens are less likely than organic sunscreens to cause irritation and sensitization. UV blocking fabric would be a great option for infants and those with sensitive skin.

Protective clothing is an option for youngsters, those with sensitive skin and in situations where reapplication is not possible. The ultraviolet protection factor (UPF) is a measure of how effective a fabric is at blocking UV radiation; a rating of 15-24 indicates good protection, 25-39 very good protection, and 40-50 excellent protection. Washing clothes with RIT Sun Guard can confer a UPF of 30.

If you have concerns about your exposure to the sun, please consult with your physician. Health Professionals of Winfield is conveniently located at the Physicians Pavilion on the William Newton Hospital campus. To schedule an appointment, call 620-221-4000

Dr. Meyer has been practicing at Health Professionals of Winfield since 2017 and is board certified in internal medicine. She specializes in the prevention, diagnosis, and treatment of adult diseases. If you have comments or story ideas, call 620-221-2300, ext. 1113.

The "Weekend Check-Up" is a regular health column published in the Cowley Courier Traveler penned by employees and friends of William Newton Hospital.