First of all, before starting to smoke at the age of 19, I was in awesome shape. High school state champ swim team good of shape. I have also always been a long distance hiker. It's not uncommon for me to go on 20 mile hikes....and I'd smoke while doing that. Until the age of 30, I had never had sinus problems nor heartburn....ever.
I smoked 2 packs a day average for 15 years. Gradually went from three packs a day, down to two, then down to one pack a day....about 5 years at each stage. I never really had a persistent smoker's cough. However, I would cough uncontrollably when I got winded from jumping on the trampoline with my nieces, or running. Then, when I turned 30, I really began to notice my breathing becoming more shallow, chest tightening, weezing, sinus problems, heartburn/acid reflux problems, cold feet in a warm room temp, and I felt like hammered dog crap every day. Every morning, I would literally wake up with the thought of "holy s***, I really need to quit smoking, or I'm going to die an early death". Which brought on my worst side affect of smoking, mental stress. No matter how much my smoking had decreased, I had an ever growing mental sense that I was dying a slow miserable death....because my physical symptoms of the cigarette abuse were getting worse. Aside from the actual physical affects, just the mental impact alone was enough to make me feel like I was 60 (I'm only 34), and death was right around the corner. Drove me into depression, even. That finally drove me to quit a month ago.
With that all said... When I quit, I took Chantix. I was going to quit...period. I quit smoking four days after starting the Chantix. Didn't take a drag from anything for 8 days...and then I lowered my dosage on Chantix...and then the urges came back. I had an e-cig a few years ago, but clearly I wasn't ready to quit then, because I gave it up quickly....but I did actually like it. So I decided to go out and find another cheap one to get me over the hump. I've now graduated to a 510, and have decided that I'm good with just vaping for the rest of my life. My wife is also cool with it.
Now, my experience in regards to your question... The 8 days I hadn't had anything, I didn't really "cough" anything up, but I was pulling up phlegm and blowing my nose a lot, which told me my sinus' were beginning to clear. After a month without regular cigs, my breathing is deeper, sinus' are still clearing, my feet are warm again, my heartburn/acid reflux has really subsided, chest no longer tightening, weezing is gone, and I feel well rested in the morning with no thoughts of death...so my mental state is better. Hiking also feels better.
Sorry that was so long, and maybe no one will read it far enough to make it to this point...but I wanted to give the full layout of my experience before, during, and after smoking cancer sticks. Good luck to you, and to anyone else choosing to give up the smoking. It's tough, but once you find an e-cig and a flavor you can stick with...you'll never go back.