There is an aspect of this thread that I find interesting as a long time ScubaBoard participant. We have had a number of threads in the past related to smoking and Scuba. This is the first one I can remember in which there has not been a number of posters insisting that smoking is not a problem and even (ridiculously) that smokers have better SAC rates than non-smokers for some absurd reason related to their lungs being used to working with less oxygen.
In all my years on ScubaBoard, I have entered into many a contentious fray on many a contentious topic. I have had a number of my posts removed, but only because they responded to another post that was deemed inappropriate. I have never had any of my posts moderated on their own merit. The closest I ever came was on a thread much like this. I made a post similar to the one I made above--pretty benign and straightforward, in my view. I received a warning message from a moderator about it. Now that I am on the staff and know how things work, I know what happened. Some smoker had reported my message and complained that it infringed on smoker's rights to do as they pleased by suggesting that what they were doing was not the best thing in the world. In response, a staff member had contacted me to suggest I present my views on smoking in a more balanced fashion.
I wonder if this change is just a chance occurrence determined by who happened to be reading the threads, or if it indicates a change in overall viewpoints.
I did my cert last September, days before my 51st birthday. (Yay!) I had been a smoker since the age of 14, pack a day.
In January I went for my annual. The only issue found was with my red blood cells. The count was high, and the cells were slightly larger than normal. According to my doctor (I am not a doctor) this was directly attributable to my smoking and its impact on my ability to deliver oxygen to my body. As I understand it, CO2 from smoking takes up space required to carry oxygen, so more cells are needed to do the same work. Again, as I understand it, the red cells are supposed to carry CO2 out and oxygen in; smoking interferes with this and results in CO2 being carried in as well, replacing the oxygen it is supposed to carry in.
All other things equal, if each breath delivers less oxygen, it will take more / heavier / faster breathing to deliver the same amount in the same time. The implication is that regardless of your SAC, it can be better without smoking and the CO2 interference.
Among other reasons, having just discovered diving, I was not ready to give it up straight away.
So May 11 was my quit date. I haven't looked back. Champix (Chantix in the US) was my drug of choice, and I had no issues. I was ready.
And I can sate, from my own experience, IT MAKES A DIFFERENCE. All activity is less tiring to me. My breathing while diving is more relaxed. My air consumption is improving. My blood is returning to normal levels.
A smoker has to be READY to quit. Believe me, I get that. I will never be a holier-than-thou ex-smoker. But that does not mean that I did not always know what it was really doing. Any smoker who tells themselves it is not having an impact is being delusional. It is ok to admit that you understand its negative consequences while continuing to do it. It is your choice. But it is insulting to others when you claim it is either neutral or beneficial. We are all smarter than that.