Sunlight and the circadian rhythms in your skin

June 16, 2015

Anecdotally (or so I’ve heard), skin cancer frequently develops in places not regularly exposed to sunlight. If true, this flies in the face of the dogma which goes something like this (Tl;dr): ultraviolet light from the sun penetrates into the nuclei of skin cells and damages DNA; if the right [wrong] genes are altered/mutated and the mutated cells proliferate, it can develop into a tumor (gross oversimplification).

So, what might explain the discord?

Interestingly, Bill also cites a 2003 study that concluded “lifetime sun exposure appeared to be associated with a lower risk of malignant melanoma.”

I’m really only sharing this article because it’s summer, hot out, and everyone out there is probably worrying about sunscreen. I’ve never been convinced. Sun does a lot of interesting things to/for us, perhaps most importantly vitamin D production, which (ironically), a deficiency in is linked to many cancers.

It’s probably not the sun that’s giving us all melanoma; instead, it’s probably a lack of sun combined with too much artificial light at the wrong times. (And diet, and exercise, and the rest. It’s never that simple. The point here is that if the sun was killing us, our species wouldn’t have made it this far.)