So I'm extremely new to the vaping community but I am one to do plenty of research when I make a decision. In my hunt for information I found that a lot of people feel that the VG has less "variables" and may be better for you than PG. Not to mention the increased amount of vapor. But there also seems to be quite a bit of discussion about the side effects (mainly large amounts of phlegm in the lungs) from vaping 100% VG. But I've created a hypothesis that I believe to be the culprit here and I thought I'd share .
So before I started vaping I'd had some prior experience with vegetable glycerin in (don't freak out!) my hair care regimen. I stopped using it though because glycerin is a humectant which draws moisture from a moist place to a dry place. So with hair that may mean that moisture is being drawn from your hair out into the air... or vice versa but it depends on which part is more dry. Stay with me! I do have a point .
So in finding out how mucus is created in the body I discovered mucus begins in the nasal passage. And a dry environment dries out the mucus in the nasal passage making it thick and difficult to flush out. That causes the mucus or "phlegm" to build up and eventually make it's way down to your lungs where it's then coughed up. This happens naturally if maybe you live in an area where the air is dry. The air everywhere gets dry in the winter months and can cause some people to produce more phlegm simply because it's cold outside.
Since VG is a humectant, it may very well be pulling moisture from your nasal passage and out into the air as you exhale your vapor. This dries out the nasal passages which then makes the mucus thick and hard to get rid of, hence the buildup. And then just as in a dry environment, that buildup eventually makes it's way down to your lungs at which point that chest heaviness comes along and you start feeling the need to cough up the phlegm. A humidifier or drinking lots of water (not other liquids ) should help. But it sounds like the very nature of VG itself is what causes this problem. And one may or may not have trouble with this depending on how hydrated they are. Also keep in mind that people with consistent allergy problems will have the same sorts of issues. As a matter of fact, if you have allergy problems, they could be exacerbated by the all VG juice, I would imagine.
Now if the mucus is green or yellow... that's a whole different story. That means your body is treating it like an infection and is trying to expel it from your body. Obviously not good.
I'm not a doctor, but it looks like the science here could make sense.
But that, of course, is just my humble opinion :-). Any thoughts?
Why does the Nose Make Mucus & Why is snot Green? - The Naked Scientists 2008.01.26
Read more: What Causes Mucus in the Throat? | eHow.com What Causes Mucus in the Throat? | eHow.com