Mine downturn came a little early this year, shortly after my last post.
OK I think I may have found [part of] the answer, and my little booklet that came with the compact version gave me the clue!
The verilux light manual says:
If you feel a sort of edginess, as though you have consumed too much coffee, it may be time to turn off the unit or reduce the intensity of the light.
Like I feel in mid-autumn?
Don't get me wrong, it's awesome to have more energy, but it did also feel a bit like I'd chugged a line of Red Bulls.
If you're following along at home, I believe a few of the articles I cited above pointed out that UV light helps autoimmune disease
independent of Vit D levels so it is now viewed as a good thing 'in and of itself', though I don't think science is entirely sure why.
As someone who spent nearly a decade teaching middle-schoolers science, I am aware both that the angle of sunlight changes in the autumn, and that the scatter through the atmosphere can affect wavelength, so I began to wonder if there was something special about autumn sunlight and/or something particularly disadvantageous about winter sunlight.
So I looked it up, and lo and behold, there is!
There are three classes of UV wavelength: UVA, UVB, and UVC. UVC rarely makes it to earth, so we don't bother with it, much.
UVA is penetrant, going right through your clothes and through several layers of skin, so it will not 'give you a tan' and it won't activate anything on your skin's surface to make our lovely Vit D active.
That's allll UVB, which seems to have numerous health effects beyond Vit D activation. I'd have to read more carefully to be sure, but there are a lot of articles on UBV and Vitamin B12, and I've noted symptoms associated with low B12 are going up this time of year, too -- two days ago, before I read these articles, I had doubled my morning dose of my multi-B. UVB decreases blood B12 so I'll have to be cautious, but I'm wondering if it's 'more efficient use' rather than anything else.
From November to February, there is little/no UVB that 'makes it through' the atmosphere. One study says "effectively none". Though others are less doomsday-ish, all say that this time period you'll get far, far less UVB to reach your skin. Even in the brightest winter sunlight, you're standing in a wash of UVA.
I sat in front of my mini light for 10 minutes as the packaging initially advised, with my glasses off and typed this. Over the course of 10 minutes, the pain at the back of my neck eased, and I perked up a little bit. Now, twenty minutes later, I feel the aches returning. Very interesting.
I ended up skimming and scanning about 20 articles, but here's the one that does the best job of summarizing most of what I found:
UVR, Vitamin D and Three Autoimmune Diseases—Multiple Sclerosis, Type 1 Diabetes, Rheumatoid Arthritis.
And, btw, stumbled across this one:
The beneficial effects of vitamin D3 on reducing antibody titers against Epstein–Barr virus in multiple sclerosis patients