Coughing is a way to clear your trachea (airway) of fluid, food, particles or irritants. Coughing also moves mucous up to your throat where you can spit it out (if you so desire).
How Coughing Works
Coughing is just grunting, but with more force. In fact, grunting, coughing and clearing your throat are all essentially the same action.
Try it. Grunt.
Grunt like you're lifting something very heavy. Go ahead -- I won't tell anyone -- now grunt like you mean it. Pay close attention to how you make that straining sound. You've just coughed in slow motion. Of course, the point of coughing is to work quickly, the rush of air a cough generates is the way stuff is moved out of your airway.
Look at a cough in three steps.
- First, you close your throat. It's the same way you hold your breath to swim underwater. Your vocal cords are forced together hard enough to be airtight. Nothing can get in and nothing -- not even air -- can get out.
- Second, you push. Using the same muscles in your chest that you use to blow out birthday candles, you push against your closed throat. Nothing is coming out, yet, but it will.
- Finally, you let loose. Once you've built up a little pressure behind those vocal cords, just open them up. Voila! A cough is born.
That rush of air comes out as fast as 64 miles per hour, sending mucous, particles and droplets zooming out more than 6 feet in front of you. If those droplets contain bacteria or viruses, it means you could infect other folks -- a great reason to cover that cough.
Pulling the Cough Trigger
Now that we know what a cough is, what makes us do it? Coughing seems like a simple problem, but it's actually very complicated. There are three types of cough:
Voluntary. We cough on purpose -- like what you did after reading the steps above. Don't deny it, I know you were sitting in front of your computer coughing away, testing my description.
Reflex. This is the type of cough that probably leads you to read this in the first place and the type of cough we'll spend more time on. Our bodies don't like it when things block airflow in our lungs and airways. So, anything that tickles, touches or blocks airways gives us an urge to cough. The stronger the urge, the more likely we won't be able to stop it. Also, the stronger the urge, the stronger the cough.
Behavioral. Sometimes it's the act we get used to. You have habits and mannerisms that folks around you have probably pointed out. Maybe you touch your nose all the time. Maybe you play with your hair. Some people cough.
The most important of these three is a reflex cough. Infections, irritants like smoke, some heart conditions, asthma and airway obstructions all trigger reflex coughing. When you search for causes and treatments of coughing on the Internet, reflex coughing is what you're asking about.
Reflex coughing is such a complicated process, we don't fully understand how it works yet. There isn't a single place in the lungs, throat or airways that triggers a cough. There isn't a particular place in the brain that processes the urge to cough. It's all interconnected with several possible triggers and gray areas, sometimes controllable and sometimes not.
If you can't move air through your air passages (bronchi or trachea) you may feel short of breath or you may feel the need to cough -- or both. Constricted airways from swelling, inflammation or mucous could cause that feeling.
My grandparents always spoke of having a "tickle" in their throats when they needed to cough, which could be from some sort of irritation like smoke or even the same type of allergies that cause itching of the skin.
We know for sure that fluid or objects that come in contact with your vocal cords (found in the larynx) will cause them to spasm and cause coughing. Coughing, remember, is all about protecting your airways and lungs.
The only way to truly treat a cough is to fix the underlying cause. Lots of cough medicines exist on the market in prescription form and over the counter, but nothing works perfectly. Some cough medicines are only sold as cough medicines today because they always have been, even after research has not shown them to be effective.
Since coughing is a way to protect the airways and remove mucous and germs from the lungs, it might not be a good idea to get rid of a cough -- especially one that's producing mucous. Some cough medicines aren't intended to suppress coughs. They are instead intended to make mucous thinner and help coughs work better. Those medicines are called expectorants. Medicines that suppress coughs are called cough suppressants. Always read the label to see if you're buying a cough suppressant or an expectorant.
Home remedies abound for coughing. There's no way I could cover all the possible examples here, but depending on the type of cough, there are a few things you might try that don't require a trip to the pharmacy.
One example is simple honey. In one study, honey did better than dextromethorphan -- a common cough suppressant -- at reducing coughing in kids at night. Dextromethorphan did about as much good as no treatment at all. So, saying honey is better than nothing at all isn't really setting the bar high, but it is literally better than nothing.
Xie, X, et al. "How far droplets can move in indoor environments--revisiting the Wells evaporation-falling curve." Indoor Air. Jun 2007
McGarvey, LP, and AH Morice. "Clinical cough and its mechanisms." Respir Physiol Neurobiol. Jul 28 2006
Davenport, PW. "Urge-to-cough: what can it teach us about cough?" Lung. 2008
Paul, IM, et al."Effect of honey, dextromethorphan, and no treatment on nocturnal cough and sleep quality for coughing children and their parents." Arch Pediatr Adolesc Med. Dec 2007