DEAR DR. ROACH: I have a question about suntanning. First off, I want to say that I get yearly skin cancer checks, love the sun, and hardly ever use suntan lotion. I monitor my time outside, so as not to get a sunburn. I see warnings about certain days being high ultraviolet (UV) days.
Are they talking about UVA or UVB, and which one gives you a tan? — S.K.
ANSWER: You’re not going to like my answer, because all types of UV light exposure, whether they lead to a sunburn or suntan, cause damage to the skin and lead to an increased risk of skin cancer. A tan from sunlight leads to a small degree of protection against further UV light damage, but there is still ongoing skin damage with UV light exposure.
Even people with very dark skin are susceptible to skin cancer, although their risk is a lot less than others.
UVA light is more constant throughout the year and penetrates deeper into the skin. UVB light is stronger near the equator, at higher altitudes, and closer to the summer solstice. The UV index reported by the National Weather Service considers both UVA and UVB light in its calculations, as well as the time of year, altitude, and cloud cover.
Both UVA and UVB light cause the skin to tan, but tanning from UVA light alone (for example, in a tanning machine) doesn’t provide any protection from the sun. So, while I am at least glad that you aren’t exposing yourself enough to get burned, I don’t agree with being out in the sun to get tanned.
I do recommend the liberal use of a sunscreen with protection against both UVA and UVB. It needs to be used in a largeenough quantity to provide protection -- approximately an ounce for an averagesized body, plus another teaspoon for the face and neck. I recommend a high-SPF sunscreen (30 or more). I buy mineral sunscreens such as zinc oxide or titanium dioxide for myself and my family.
Finally, sunscreen needs to be reapplied regularly, especially when exercising or swimming.
Staying out of the sun, wearing sun-protective clothing, and wearing sunscreen will not only help you avoid cancer, but also help you avoid problems that I see in my older patients, who did what you did when they were young.
Now they have thinned skin that bleeds easily, as well as “age spots” and other signs of skin damage from the sun, including wrinkles.