We have to breathe in order to live. The oxygen, which is essential for us, is cleansed and its heat and moisture are regulated as it passes turbulently down the narrow channels of the nose. Thus, the air we breathe is made ready for service to the alveolus in the lungs. In this way, approximately fifteen square meters of air, which is inhaled with 23,000 breaths daily, is processed in the nose.
The area behind the nostrils has been equipped with an acclimating system that is astonishingly sensitive and which scientists have difficulty explaining. This system not only regulates the heat and moisture of air, but at the same time, it possesses a mechanism that perceives harmful molecules in the contents of the air and gives an alarm. By stimulating the nose's mucosa, this alarm mechanism shows activity by evacuating with the speed of a hurricane the air in the lungs via the nose and mouth-this is what we call sneezing. As a result of sneezing, the harmful matter that entered the body with the inhaled air is expelled from the body.
How and why do we sneeze?
It is a Divine blessing that we do not become ill frequently in spite of the millions of microorganisms that enter our body everyday mainly through the air we breathe. The microbes that enter our noses with the air we breathe are caught together with dust by tiny hairs here called cilia. Those that escape here are asked for a password by the anti-bacterial mucus secretion emitted by the epithelium tissues in our noses. In order for smells to be perceived by the nerve cells of molecules, the thickness of mucus must be around .06 mm. If the mucus layer were thicker, our sense of smell would be decreased, and if it were thinner, the defense system would weaken and cilia would be easily harmed. In addition, with its content and density, this secretion is responsible for filtering foreign particles in the air and for moisturizing the air to make it suitable. Because it is dangerous for things to pass this point, the body's alarm that we call sneezing kicks in and microbes are expelled in this way. Sneezing is one of the most important defense mechanisms of the upper respiratory system. When the thresholds of the special nerve cells in the nose are stimulated, the signals reach the brain and the sneezing reflex kicks in. The mucus tissues are stimulated, mucus is secreted and the capillaries widen. Meanwhile an itching or tingling sensation is felt in the nose. As a result of the warning coming from the brain to the head, neck and stomach muscles, air is closed into the area where the vocal chords are and pressure is greatly increased in the lungs. Later, while the air is suddenly and loudly forced out, the foreign matter in the nose and respiratory path are thrown out. Because the nerves responsible for sneezing are also connected to the eyes, tears are usually secreted during sneezing and at this time the eyes involuntarily close.
In addition to the discomforts of the flu, the common cold, and bronchitis causing sneezing, external factors like nose polyps, flying pollen, dust, perfume, animal hairs and even suddenly looking at the light can also cause it. Because some people are sensitive to certain factors, they can be affected faster and they will sneeze. Some are more amenable to sneezing during certain periods. For example, it has been determined that pregnant women are more inclined to sneeze due to the hormonal change they are experiencing. It has also been established that the members of some families sneeze consecutively in certain numbers (3-5 times); this situation supports the idea that sneezing attacks can be hereditary. It is known that men sneeze more than women and that white people sneeze more than black people. One out of five people sneeze when they look at a bright light while walking in the dark. Due to the sudden reflection of light, the pupil of the eye contracts and the emission of tears increase. This emission reaches the upper division of the nose cavity by means of the tear ducts and, stimulating the mucus tissue in the nose, it triggers sneezing. In illnesses such as the common cold, the mucus in the nose quickly triggers sneezing because it is more sensitive.
Beware of cluster bombs
Sneezing is one of the rare moments when the body desires a situation different from its normal functioning. Sneezing and coughing lead to a movement of air strong enough to break the mucus bond, and as a result, droplets are formed. It has been established that the speed of air and the particles in it while being expelled from the mouth at this time is close to 100 miles per hour. Those who carry the viruses of illnesses like the flu scatter about close to one hundred million microorganisms during sneezing-like a cluster bomb. From 2,500–5,000 droplet seeds can remain in the air for hours in the cloudlet that has been formed. As the diameter of the droplet seeds decreases, their period of staying in the air increases. The diameter of droplet seeds that remain in the air for a long time and cause the spread of illnesses is between one and five microns.
Rather than food and drink, tuberculosis spreads by deep respiratory movements like sneezing and coughing via droplets loaded with bacillus. Dispersing in the air into smaller particles, the droplets are inhaled by healthy people by means of the respiratory path.
If necessary precautions are not taken in regard to a viral infection, it can spread throughout the world in one month, because the droplets carrying the virus can travel forty meters when you sneeze, six meters when you cough, and two meters when you talk. For this reason, illnesses like the flu which spread with droplets are frequently seen during the winter. For one person sneezing several times in places where there are crowds of people means that the virus spreads to hundreds of people within a few minutes.
Is sneezing beneficial?
The movement of cilia in the upper respiratory path is very important in regard to the health of the lungs. They hold the harmful matter coming with the air, trigger the sneezing reflex, and together with mucus, prevent them from entering the lungs, thus performing a very important protective duty. The expulsion from the body of matter that is probably harmful together with the air in the lungs is a blessing that provides a person with a great benefit. Consequently, formerly natural powders like black pepper known as snuff were breathed into the nose in order to sneeze. While sneezing, the brain and cardiovascular veins expand and tear and sinus ducts open; thus, the dead air we normally cannot exhale is forced from our lungs.
When sneezing, a high amount of pressure is generated in the body, especially in the stomach area and brain. Due to this pressure, a lot of blood goes to the cardiovascular veins, and in fact, serious situations like fainting can occur during sneezing attacks. However, sneezing is beneficial to a healthy heart. Fully closing the mouth and holding the breath while sneezing can bring about bursting and tearing in the lungs. The ribs can even break with an intense and unbalanced sneeze. If a person tries to stifle the sneeze after the sneeze reflex has occurred by closing his mouth and nose, he can harm the brain and bring on paralysis or when the pressure increases in the capillaries in the brain, bleeding can occur. In this situation, people, especially those who have undergone an operation, can be seriously harmed. In addition, veins in the eyes can expand and rupture. When sneezing is triggered, a person should relax and not prevent the sneeze.
In addition to providing protection against harmful things that have entered the respiratory system, sneezing is a reflex that is a means for relaxation, relief and invigoration of the body. If this reflex had not been put in the body, it would be difficult to escape many harmful things that would give discomfort. During sneezing, the rest period after diastole of the heart increases. This is probably the reason why we say, "Bless you" when someone sneezes. Prophet Muhammad, peace and blessings be upon him, said, "One of the six rights of a believer over another is to make a prayer when he or she sneezes," and "One of the times when prayer is accepted is at the moment of sneezing." It was related that the Prophet, peace and blessings be upon him, "covered his face with his hands or a cloth when he sneezed and he lowered his voice."
We are being reminded of the value of our health which God bestows upon us anew each time we sneeze. Sneezing is a cloud of mercy not only for us, but also for those who witness this moment with prayer and with whom we share feelings of gratitude.
Adem Arikanli is a freelance writer from Turkey with an interest in health and biology.
Figure 1: In order to meet the body's need for oxygen, which is essential for us, the nose cleans and regulates the heat and moisture of oxygen as it passes turbulently down the narrow channels of the nose. Thus, the air we breathe is made ready for service to the alveolus in the lungs.