It all boils down to a choice, the choice between vigorous smoking or vigorous fucking. "What choice", I hear you yelling, "I do both!" For a while you do, sure. But then COPD sets in. And you find that you made your choice long ago - vigorous smoking is suddenly your only remaining alternative. Because you now have COPD - Chronic Obstructive Pulmonary Disease.
This is how it works:
Cigarette smoke attracts inflammatory cells into the lungs, from the surrounding body. These cells start releasing an enzyme, ELASTASE, which evolution has devilishly designed to break down Elastine, the nice structural material of lung tissue. But don't despair -- evolution also gave us an ELASTASE inhibitor, AAT (alpha-1 antitrypsin). So the lungs should be safe from the effects of the evil ELASTASE, protected as they are by AAT, right? Well, yes -- sort of. Normally, yes, of course. But if you smoke a lot, then the number of inflammatory cells that smoke attracts -- each of them releasing its own dose of evil ELASTASE, remember -- gets unmanageably large. And so the total amount of ELASTASE becomes far too large for the available AAT to handle.
A different kind of SOB
The result is that uninhibited evil ELASTASE starts breaking down your nice Elastine and thus dangerously weakens your lung tissue. In combination with mechanical stresses from coughing (never heard of "smoker's cough"?), the walls between the individual alveoli break down and larger cavities form. The total surface area of these larger cavities is much smaller than that of the original alveoli. Because of the reduced contact area between the air in the lungs and the blood stream, the blood can no longer take up as much oxygen as it needs, leading to a terrible SOB. Unfortunately, in medical parlance SOB doesn't mean Son Of a Bitch. Rather, it is short for Shortness Of Breath. If it gets short enough, it will kill you. Until then, it makes all ordinary physical activity difficult or impossible - preventing you from running, climbing stairs sprightly, fucking vigorously. The sum total of this particular misfortune is called Emphysema.
Emphysema seldom comes alone. It usually comes packaged with Chronic Bronchitis. To you Chronic Bronchitis means that the walls of the small air pipes (bronchi) in your lungs are constantly inflamed. The inner lining of the pipes starts producing mucus, so much of it that the airways become partly clogged and narrowish. OK, but there are small waiving hairs, cilia, which wave unwanted stuff away from the airways! And Macrophages, which eat toxins and all kinds of pulmonary trash! Past tense please - there ONCE WERE cilia and macrofages. These have long since been inactivated by the toxins from all that cigarette smoke and / or pot that you inhaled with such pleasure.
So here you are, presented with a nice package of COPD, combining emphysema and chronic bronchitis. You can't do anything about it. There is no way to recover what is lost. And the degradation continues unyieldingly, whether you stop smoking or not. Of course, if you stop, then the rate of degradation decreases.
Not getting the message
COPD is not an odd freakish little disease that leaves most people alone. It's in fact the fourth commonest cause of death in the Western world. Only it has not been correctly diagnosed, until fairly recently. Lung cancer, undeservedly, took all the headlines. But COPD is much, much, much more common. True, not all smokers get it, some seem to have genetic protection against COPD. But uncomfortably many don't get it -- the message -- so they get COPD.
In my case I made my choice in the nick of time. I still have 75% left of my lung function, so I can yet moderately vigorously practice this other thing, the thing you are able to do when you are not vigorously smoking. And for some curious reason my red blood cells and their haemoglobin have grown much more efficient since I quit smoking, so the sum total of my bad lungs and my good blood amounts to the equivalent of 87% lung capacity.
General COPD information: http://www.lung.ca/copd/
British site with COPD statistics: http://www.priory.com/cmol/copd.htm
Boeringer (pharmaceutical company with COPD relief drugs): http://www.airwavesonline.com/
A COPD patient informs: http://www.copdadvocate.com