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sun exposure through glass

Commented on November 20, 2013
Created November 19, 2013 at 5:45 PM

Now that winter is almost upon us ...

Is getting sun exposure through glass (e.g. sitting by a window in my warm home) as beneficial as sitting outdoors in the sun? I know that in winter the sun is low, so I'm not getting *that* much exposure anyway. Yes I know there are other benefits of being outdoors. Don't get all Paleo-fanatic on me! I just want to know if anybody is informed about vitamin-D etc production from indoor exposure.

Dc6407193ba441d1438f6f0c06af872b

(4400)

on November 20, 2013
at 11:57 AM

I briefly checked this out. As you say, apparently glass filters out most uvb (which does help with D production) and allows through a lot of uva (which doesn't). As you say. This answers it, unless somebody else knows differently. Conclusion: Staying indoors and getting sun through the glass is a bad idea.

543a65b3004bf5a51974fbdd60d666bb

(4493)

on November 19, 2013
at 11:29 PM

Now that winter is almost upon some of us ...

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2 Answers

0
543a65b3004bf5a51974fbdd60d666bb

(4493)

on November 19, 2013
at 11:23 PM

not so much an answer, but how i remember what UVA & UVB are (at a superficial level),

uvA Ages. wavelengths penetrate deeper in to the skin & do more damage (think wrinkles).

uvB Burns. tans the skin, think Vitamin D (of course you want to avoid actually burning).

... & as far as i recall uva can travel through glass, whereas uvb cannot

Dc6407193ba441d1438f6f0c06af872b

(4400)

on November 20, 2013
at 11:57 AM

I briefly checked this out. As you say, apparently glass filters out most uvb (which does help with D production) and allows through a lot of uva (which doesn't). As you say. This answers it, unless somebody else knows differently. Conclusion: Staying indoors and getting sun through the glass is a bad idea.

0
5661757f5a7ad1d09c44d7b3ce9b533f

on November 19, 2013
at 07:42 PM

You probably don't want to get your exposure thru glass as that allows only some potentially damaging rays thru while preventing the tanning/VitD-stimulating ones from reaching you, the worst of both worlds.

Some links:

http://www.skincancer.org/prevention/are-you-at-risk/sun-hazards-in-your-car

UV exposure is cumulative, and research has proven that skin exposed to sun shining through window glass, even in the office, can over time lead to significant skin damage.1,2 The UV exposure we receive driving a car especially adds up. In a US study by Singer, et al, the researchers found asymmetric photodamage (sun- induced skin damage) on the face, with more brown pigment (color) and deeper wrinkles on the left.3 The more time subjects spent driving a vehicle, the more severe their photodamage on the left side. Reinforcing this research, in countries where the driver’s side is the right side, people tend to develop more sun damage and skin precancers on the right.4 Certain precancers can turn into squamous cell carcinoma, the second most common form of skin cancer.

http://www.medical-hypotheses.com/article/S0306-9877%2808%2900599-9/abstract

Cutaneous malignant melanoma (CMM) has been increasing at a steady exponential rate in fair-skinned, indoor workers since before 1940. A paradox exists between indoor and outdoor workers because indoor workers get three to nine times less solar UV (290–400nm) exposure than outdoor workers get, yet only indoor workers have an increasing incidence of CMM. Thus, another “factor(s)” is/are involved that increases the CMM risk for indoor workers. We hypothesize that one factor involves indoor exposures to UVA (321–400nm) passing through windows, which can cause mutations and can break down vitamin D3 formed after outdoor UVB (290–320nm) exposure, and the other factor involves low levels of cutaneous vitamin D3. Most of the popular sunscreens on the market only offer meaningful protection against UVB rays. I get that. As much as I love a nice dose of vitamin D, too much UVB exposure can lead to sunburns and skin damage. But in letting through most of the UVA while blocking out UVB, they are doing users a massive disservice. The UVA ends up being a huge problem because people are staying out longer without burning. They figure they’re safe, but it’s a false sense of security: isolated UVA exposure (along with decreased D) seems to increase the chance of developing melanoma, the really dangerous kind of skin cancer.

http://www.marksdailyapple.com/vitamin-d-confounding-factors/

In the end, it seems like getting full spectrum UV is essential for obtaining D3 and protecting yourself. In this case, what works best is what’s most natural – full spectrum sunlight without burning.

http://www.archevore.com/panu-weblog/2009/8/19/how-much-sun.html

Bottom line to my hypothesis: tolerable sun exposure for your skin type should be roughly the same as what optimizes your Vit D levels. Beyond that may age your skin prematurely. You can search for more info as you see fit of course, Hope this helps.

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