Smokers frequently suffer mucous build-up in their airways. This condition is referred to as chronic mucus hypersecretion, or CMH. It happens because smokers' lungs make more mucus in an effort to clear away toxins inhaled with smoke. As thick and gooey mucus fills the airways, it gets harder to clear it all away. Bacteria and viruses thrive in these conditions, frequently leading to smokers catching colds.
Increased Production
Cigarette smoke contains tiny particles, also referred to as particulate matter, of toxic substances. Your body's natural reaction is to get rid of the toxins, and one way to achieve this is to trap toxic particles in mucus and then clear it away. According to a 2010 report in the journal "Toxicology In Vitro," L.E. Haswell et al. were able to demonstrate that cigarette smoke causes the lungs to make more cells which are capable of secreting mucus via a mechanism called mucociliary differentiation. That simply means that production of new cells in the lungs is geared toward making the cells capable of secreting mucus. As more mucus-secreting cells are made in the smoker's lungs, they produce more mucus.
Decreased Clearance From Airways
There are miniature hairs in human airways called cilia. Cilia move rhythmically to clear away mucus, a process referred to as mucociliary clearance. Smoking causes slower movement and shorter length of cilia, as reported in PLoS One by P.L. Leopold and colleagues in 2009. As smokers produce more mucus to begin with, damaged cilia can't keep up with clearing away the mucus from the airways.
Structural and Functional Changes of the Airways
S.S. Braman and M. Abu-Hijleh pointed out in their article in "Otolaryngologic Clinics of North America" in 2010 that chronic overwhelming of airways with toxic, or noxious particles, as is the case with smoking, may cause damage to the lungs. Due to structural damage, lungs of smokers may loose capacity to breathe, as well. Chronic overproduction of mucus causes smokers to have especially thick mucus called phlegm. Bacteria and viruses grow in phlegm, making smokers more prone to colds. When infected, phlegm turns from clear or white to green.
Treatment Strategies
As smokers tend to have more mucus than non-smokers, treating respiratory conditions such as cough caused by a viral infection requires medicines that would have strong mucus-breaking, cough-inducing and airway-relaxing effects, as suggested by a Russian researcher I.L. Kliachkina in the 2009 issue of "Military Medical Life." Some of these are available over-the-counter, while the airway-relaxing medication needs a prescription.
Prevention Strategies
A study by M. Broekema et al. in "American Journal of Respiratory and Critical Care Medicine" in 2009 found that ex-smokers with asthma had similar-looking lungs to non-smokers with asthma. This suggests that quitting may reverse the damage caused by smoking. Therefore, smoking cessation remains the number one prevention strategy for damage caused by smoking, including mucus over-production.
T. Harju et al. reported in "The Clinical Respiratory Journal" in 2010 that colder temperatures lead to more colds, so bundle up to stay warm, and to reduce your chances of getting a cold.
