Chapter 3: Sneezes and Coughs: The Body's Emergency Exits

A Tickle, a Breath and a Blast

It starts with a tickle deep inside your nose. Your eyes start to water a little. You take a quick breath in, and then another, and your face scrunches up. You could not stop it now even if you tried. Then, all at once, it bursts out of you: ah-choo!

You have sneezed many times in your life. You have coughed many times, too. Maybe you sneezed when dust flew up from an old book, or when you sniffed some pepper, or when you had a cold. Maybe you coughed when a crumb tickled your throat, or when you laughed while drinking water.

Sneezes and coughs can feel a little rude or embarrassing. They are loud, and they often happen at the worst moment, like in the middle of a quiet room. But they are not mistakes. They are two of the most useful tools your body has for protecting itself.

In the last chapter, you learned how the nose catches dust and germs with its hairs and its sticky mucus. Most of the time, that gentle cleaning is enough. But sometimes something gets stuck, or tickles the lining in a way the body does not like. Then your body needs a faster and stronger way to push it out.

That is what sneezes and coughs are for. You can think of them as emergency exits. In a big building, emergency exits are special doors that let people get out quickly when something goes wrong. Sneezes and coughs let unwanted things get out of your breathing passages quickly. In this chapter, you will find out how these exits work and how to use them kindly.

What Is a Reflex?

A sneeze is a kind of action called a reflex. A cough is very often a reflex too. A reflex is something your body does automatically, without you having to decide to do it. Reflexes happen very fast, often faster than you can think.

You already know other reflexes, even if you have never used the word. When you touch something very hot, your hand pulls away before you even feel the pain properly. When something flies toward your face, your eyes blink shut. When a bright light shines in your eyes, the dark circles in the middle of your eyes get smaller. All of these are reflexes.

Reflexes depend on your nerves. Nerves are long, thin threads that run all through your body, like wires carrying messages. Some nerves carry messages from your body to your brain and spinal cord. Other nerves carry messages back out to your muscles, telling them what to do.

For many reflexes, the message does not have to go all the way to the thinking part of your brain. It goes to a part that works automatically. For sneezes and coughs, that part is the brainstem. The brainstem sits at the bottom of the brain, where the brain joins the spinal cord. It controls many things you never have to think about, such as breathing and swallowing.

Here is how a reflex works, step by step. First, a sensor notices something, like a tickle in the nose. Second, a nerve carries a message about the tickle to the brainstem. Third, the brainstem quickly sends messages to many muscles at once. Fourth, the muscles act together. The whole trip takes only a moment.

You were born with your sneeze and cough reflexes already working. Nobody had to teach you how to sneeze. Newborn babies sneeze quite often, because their noses are very small and fill up easily with milk, mucus and fluff. A sneeze is the quickest way for a tiny baby to clear its nose, since a baby cannot yet blow its nose into a tissue.

Reflexes are a bit like a smoke alarm in a house. The smoke alarm does not wait for someone to look around and decide whether there is a fire. As soon as it senses smoke, it rings. Your sneeze and cough reflexes work the same way. As soon as something bothers your breathing passages, they spring into action.

Inside a Sneeze

A sneeze begins in the lining of your nose. The lining has many tiny nerve endings that act like sensors. When something bothers them, such as dust, pollen, pepper, a strong smell or even a sudden puff of cold air, they send a message along a nerve to the brainstem. That message says, something is in the nose and it needs to come out.

The brainstem answers by getting the body ready. First, you breathe in deeply, sometimes in a few quick gasps. This fills your lungs with plenty of air, the way you might take a big breath before blowing out birthday candles. That air is going to be the push that clears your nose.

Next, many muscles get to work all at the same moment. Your eyes squeeze shut. The back of your tongue presses up against the roof of your mouth. The strong muscles of your chest and belly tighten hard. The squeeze pushes air out of your lungs very quickly and with great force.

Because your tongue is pressing up at the back of your mouth, much of that blast of air is sent up and out through your nose. The rushing air carries mucus, dust and germs out with it. In just one sneeze, your nose can be cleared of whatever was bothering it.

Did you notice that your eyes close when you sneeze? That happens almost every time, and it is part of the reflex. You do not decide to close them. The same quick message from the brainstem that tightens your chest muscles also tells your eyelids to shut.

Some people sneeze when they step out of a dim room into bright sunshine. This does not happen to everyone, but it happens to quite a lot of people. Scientists think that, in these people, the messages from the eyes about bright light get mixed up a little with the messages that start a sneeze. It is harmless, and it is just one of the curious ways bodies can be different from one another.

Sneezes often come in groups. You might sneeze two or three times in a row. That can happen because the first sneeze did not clear everything out, so the sensors in your nose are still being bothered. Your body tries again until the nose feels clear.

People are not the only ones who sneeze. Cats, dogs, horses, birds and many other animals sneeze too. Their bodies face the same problem that yours does. Dust and other bits get into their noses, and a sudden blast of air is a quick way to clear them out. Sneezing is a very old and very useful trick that many living things share.

Inside a Cough

A cough is a little like a sneeze, but it protects a different part of your breathing path. A sneeze mostly clears the nose. A cough clears your throat, your voice box and the tubes that lead down into your lungs. These lower parts have their own sensors, and when something bothers them, a cough begins.

Many things can start a cough. A crumb or a drop of water might slip toward the wrong place. Mucus might collect in your breathing tubes during a cold. Smoke or dust might bother the lining of your throat. Even very cold or very dry air can sometimes make you cough.

A cough happens in steps, just like a sneeze. First, you take a quick, deep breath in. Next, your vocal cords snap shut. The vocal cords are two small folds of tissue in your voice box, a part of your neck that you will learn more about later in this book. When they close, they work like a door that stops the air in your lungs from getting out.

Then the muscles of your chest and belly squeeze hard. Because the door is shut, the air cannot escape, and the pressure builds up inside your chest. It is like squeezing a balloon while you hold the neck closed tightly. The air inside is pushing and pushing to get out.

Suddenly, the vocal cords swing open. The trapped air bursts out all at once, very fast. As it rushes up through the breathing tubes and out of your mouth, it carries mucus, crumbs, dust and germs with it. That sudden burst is the cough you hear.

Here is something to try safely. Put your hand gently on your belly and give a small, soft cough. Can you feel your belly muscles tighten and push? Those are some of the muscles that power every cough. They are the same muscles that help you laugh, shout and blow up a balloon.

Unlike a sneeze, a cough is something you can also choose to do. You can cough on purpose right now if you want to. Sometimes you clear your throat with a small cough when it feels a little scratchy. A doctor may ask you to cough while listening to your chest. But when something really bothers your breathing tubes, the cough reflex takes over and you cough whether you planned to or not.

Coughs are especially helpful because your breathing tubes are hidden deep inside your chest, where you cannot reach them with a tissue. The only way to clear them quickly is with a strong rush of air from the inside. A cough is like a strong gust of wind blowing leaves off a long path.

Have you ever had a sip of water go down the wrong way? You probably coughed hard right away, and your eyes may have watered. That cough was your body protecting your lungs. A tiny bit of water had come close to the entrance of your breathing tubes, and the cough pushed it back out before it could go any farther. You will learn more about why this happens, and about the little door that usually stops it, later in this book.

Where Do Sneezes and Coughs Go?

Sneezes and coughs are very good at pushing things out of your body. But once those things are out, where do they go? A sneeze or a cough sends out a spray of tiny drops called droplets. Some droplets are big enough to see if light shines on them. Many are far too small to see.

The bigger droplets are fairly heavy, so they fall to the ground or land on nearby things quite quickly, often within a couple of steps. The smallest droplets are so light that they can float in the air for a while, a little like smoke from a candle. Droplets from a strong sneeze can travel much farther than you might expect, sometimes across a room.

If you are healthy and you sneeze because of dust or pepper, the droplets carry mostly mucus and dust. But if you have a cold or the flu, the droplets also carry the germs that are making you sick. Other people can breathe in those droplets. The droplets can also land on hands, tables, toys and door handles, where other people may touch them.

Droplets do not only come from sneezes and coughs. When people talk, sing, shout or laugh, they also send out tiny droplets, though usually fewer and with less force. Some germs can stay alive for a while on the surfaces where droplets land, sometimes for hours. That is why washing hands and keeping often-touched things clean are such helpful habits.

This is one of the main ways that colds and the flu spread from one person to another. A sneeze or a cough is great at clearing germs out of your own body. But if you are not careful, it can send those germs straight toward someone else. Their guards will then have to fight the same germs that your guards were fighting.

So your emergency exits need good manners. Imagine opening an emergency door in a building and letting everything rush out onto a busy sidewalk. It would be much better if the door led somewhere safe. When you sneeze or cough, you can choose where your droplets go.

Catch It in Your Elbow

The best way to sneeze or cough is into a tissue. Cover your nose and mouth with the tissue, let the sneeze or cough out, and then throw the tissue away in a bin. A tissue catches most of the droplets before they can fly into the air. Throwing it away keeps those droplets from spreading.

If you do not have a tissue, sneeze or cough into the inside of your elbow. Bend your arm and bring the inner part of your elbow up to cover your nose and mouth. Your sleeve catches the droplets. And because you do not usually touch things with your elbow, the germs are less likely to travel to toys or door handles.

Why not use your hands? It seems natural to cover your mouth with your hand. But hands touch almost everything. If you sneeze into your hand and then open a door or pass a pencil to a friend, you leave germs behind. That is why many schools teach children to use their elbow instead.

After you sneeze or cough into a tissue or your hands, wash your hands with soap and water. Rub the soap all over your hands, between your fingers and around your thumbs, for about twenty seconds. That is about as long as humming a short song two times. Then rinse and dry them. Clean hands are one of the best ways to stop germs from spreading.

It is also kind to turn your head away from other people when you feel a sneeze or cough coming. If you are sick, staying a little farther away from others helps protect them. When people are unwell, they often stay home and rest, which helps their bodies get better and keeps their germs away from friends and classmates.

What about holding in a sneeze? It is better not to try to stop a sneeze by pinching your nose and keeping your mouth tightly shut. A sneeze pushes a lot of air very hard. If the air has nowhere to go, the push can hurt the inside of your ears or your throat. It is much safer to let the sneeze out gently into your elbow or a tissue.

When the Exits Are Busy

When you have a cold, your emergency exits get very busy. Your nose makes extra mucus to wash out germs, so you sneeze and blow your nose a lot. Mucus may also collect in your throat and breathing tubes, so you cough to clear it. All this sneezing and coughing can be tiring, but it is a sign that your body is working to get rid of the germs.

Not every sneeze comes from germs. When pollen or dust makes someone sneeze because of an allergy, there are no cold germs in that sneeze to pass on to anyone else. An allergy is the body's guards reacting to something harmless, and it cannot spread from person to person. Still, any sneeze sprays droplets, so it is always kind to catch it in a tissue or your elbow.

Usually, the sneezing gets less and less as the cold goes away. A cough sometimes stays around for a while after the rest of the cold is gone, because the breathing tubes are still a little sore and are still clearing out the last bits of mucus. Most of the time, the cough slowly fades away on its own.

Sometimes, though, a cough or other symptoms are a reason for a grown-up to talk to a doctor. If a cough goes on for a long time, if it is very strong, or if someone seems to have trouble breathing, a grown-up should get help from a doctor. Always tell a grown-up how you are feeling, so the grown-up can decide what to do.

Your body has other quick protective actions too. When the back of your throat is touched by something unexpected, such as a big piece of food, you may gag. Gagging is a reflex that tries to push the thing back up and away from your throat, so it does not go down too far. It is another kind of emergency exit, guarding the place where your mouth and nose meet your throat.

That meeting place is a very important spot. Air from your nose and food from your mouth both pass through it. It is like a busy crossroads in the middle of a town, where many roads come together. And at a busy crossroads, it is wise to have guards standing watch.

In the next chapter, you will travel to that crossroads, which is your throat. You will meet some special guards that live there, called the tonsils and the adenoids. These guards do not push germs out like sneezes and coughs do. Instead, they study the germs that pass by and help your body learn how to fight them.

Key Words

Reflex: An action your body does automatically and very quickly, without you deciding to do it. Sneezing and blinking are reflexes.

Nerves: Long, thin threads that carry messages between your body and your brain and spinal cord, like wires.

Brainstem: The part at the bottom of the brain that joins the spinal cord. It controls automatic actions such as breathing, swallowing, sneezing and coughing.

Sneeze: A sudden, strong burst of air out through the nose and mouth. It clears dust, mucus and germs from the nose.

Cough: A sudden burst of air out of the lungs through the mouth. It clears mucus and other unwanted things from the throat and breathing tubes.

Vocal cords: Two small folds of tissue in the voice box. They make your voice, and they close tightly to build up pressure for a cough.

Droplets: Tiny drops of liquid sprayed out by sneezes, coughs and even talking. They can carry germs from one person to another.

Gag reflex: An automatic action that tries to push something back up when it touches the back of your throat unexpectedly.

Symptoms: Signs that the body is unwell, such as a runny nose, a sore throat, a cough or a fever.