A better understanding of wavelengths in sunlight helps explain why tanning is so risky, Elizabeth Tracey reports


Tanning is not a healthy activity, almost everyone knows by now. Johns Hopkins dermatologist Mary Sheu says ongoing research has shed light on the actual process by which sunlight exposure or that in tanning booths is such a problem for our bodies.

Shue: It's becoming really clear that UVA, which used to be thought as a pretty benign thing, the basis of tanning booths is UVA because that range of wavelength of light is what gives us a tan, suppresses our immune response. Within the 10 to 15 minutes span we have billions of DNA mutations in our skin cells. Fortunately most of those are taken out by our immune system but with the UVA suppressing that immune response, then it allows the skin cancer cells to divide and become skin cancers.     :33

Sheu notes that the first strategy for all should be to minimize sun exposure and not frequent tanning booths. At Johns Hopkins, I’m Elizabeth Tracey.