The Secrets of the Cough

Dr Vernon Coleman

If you have ever had a bad infection of your chest, you’ll have noticed that you produce large quantities of phlegm. Your doctor will have encouraged you to cough up the sputum and to spit it out.

You may have thought that the stuff you produced under these circumstances was rather unpleasant and you may have found yourself reluctant to take his advice. What you probably haven’t realised is that the phlegm is a very important part of your body’s defence mechanism.

When the respiratory tract is infected, some of the cells which line it step up their production of a special type of sticky mucus. Other cells, which have tiny bristles, then move the mucus up the tubes of your lungs towards your mouth. As the sticky mucus travels, it picks up bacteria and pollutants of all kinds. That’s why it sometimes comes out looking green, yellow, brown or black.

When you cough up the mucus and spit it out you’re doing just what your body wants you to do.

If the tiny mucus-producing cells and the small bristle-bearing cells become very irritated (as they do by continued exposure to cigarette smoke, for example) they can be paralysed. It is because these cells get paralysed that smokers are so prone to infections of the chest.

When we develop a cough most of us do our best to get rid of it with the aid of sweets and linctuses.

Although that is understandable, since coughs are something of a nuisance, it is worth remembering that the cough reflex is one of the most important reflexes in the whole of your body. If the reflex wasn’t there, you would choke to death if you ever accidentally got a piece of food stuck in your windpipe. And if you ever got a minor infection of your chest heavy enough to increase the output from the mucus-producing cells in your lungs, you’d risk being drowned by your secretions. Any doctor will confirm that far more people have died from not being able to cough than have done so from coughing.

The coughing mechanism is delightfully simple. The larynx narrows so that the air coming out of the lungs is put under pressure. When the pressure is great enough the larynx suddenly relaxes and there is an explosion of air out of the lungs. Anything stuck in or above the larynx will be blown out and the danger will be over.

That, at least, is what happens when you have a real cough. The annoying little half-hearted cough that hangs on after a cold is often more of a habit than a genuine, full-blooded laryngeal explosion.

Still, now you know why the cough is there, you might perhaps be a little less upset next time you have an explosion or two of your own!

Taken from the book `Bodypower’ by Vernon Coleman. `Bodypower’ has been a bestseller around the world for nearly forty years. It is available as a paperback and an eBook.

Copyright Vernon Coleman December 2021