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 suncreen. 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.
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, and it needs to be used in a large-enough quantity to provide protection — approximately an ounce for an average-sized body, plus another teaspoon for the face and neck. I recommend a high-SPF (30 or more) sunscreen, and 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 will 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.
Dear Dr. Roach: I read your recent column on blood pressure. I want to know what the recommended blood pressure is for a completely calm person. In other words, what if my blood pressure is always higher during the day and only at the recommended pressure when I’m totally relaxed at night? I read some comments from a longtime cardiologist, stating that you need to take many blood pressure readings during the day and get the average of these readings.
J.J.
Normal blood pressure is considered to be less than 120 mm Hg systolic and less than 80 mm Hg diastolic. It is certainly recommended to be as relaxed as possible when you get your blood pressure taken at the doctor’s office, since many people have “reactive” or “white coat” hypertension and will be treated unnecessarily based on office readings. However, a minority of people have “masked” hypertension, meaning that the office readings are normal when they actually have high blood pressure at home and at work.
What your cardiologist said about getting many readings is correct. The more readings, the better. Best of all is a 24-hour blood pressure monitor, which has been proven to be the most accurate. I recommend a certified blood pressure monitor for all my patients and consider their home readings to be more important than office readings.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to [email protected]
