By Medical Discovery News

June 12, 2015

Have you ever noticed that many times sneezes come in threes? Repeated sneezes may be your body’s efforts to get rid of irritants in the nose when the initial sneeze is not strong enough to do so.

Sneezing has different meanings in cultures around the world. The Athenian General Xenophon gave an encouraging speech to his army that went on for an hour until a soldier sneezed. Taken as a favorable sign from the gods, the army proceeded to attack the Persians, but was ultimately defeated and the general killed. One of the Pagan beliefs is that sneezing opened one’s body to Satan or evil spirits, which is how the common response “Bless You” arose. In fact, Pope Gregory VII made the short prayer “May God Bless You” a required response to a sneeze as protection from the Black Plague. As you can see, the sneeze has often been misinterpreted in history.

The sneeze can be divided into two phases. The first phase, called the nasal or sensitive phase, results from a chemical or physical irritation of the tissue lining the nose called the nasal mucosa. This signal is transmitted through nerves to the sneezing center of the brain in the lateral medulla. The second phase begins once a sufficient number of nerves are stimulated. This is when the eyes shut, a deep breath is taken, and the opening between the vocal chords closes, increasing lung pressure to allow an explosive release of air through the mouth and nose. The purpose of the sneeze is to dislodge the irritant from the nose, since an estimated 40,000 microscopic particles are expelled by a sneeze. The speed of a sneeze is estimated to be between 135 and 950 feet per second, or up to 85 percent of the speed of sound.

Allergies, infections, and inflammation of the nose’s mucous membrane (rhinitis) can trigger fits of sneezing. Allergies are the result of an immune response to substances in the environment that do not bother most people, like pollen, pet dander, or bee venom. People with allergies mount an immune response to those substances including the inflammation, which again irritates the nasal passages and causes sneezing. When you have a virus like the cold or flu, the immune response also causes inflammation of the nasal passages, which irritates the nerve endings and leads to the familiar itching and sneezing.

The sneeze is also a way for the body to reboot the environment in the nose, so the nasal mucosa can once again trap particles we breathe in from the environment. Sneezing more than once in a row is often an attempt to eject whatever is irritating the nasal passages when the first sneeze was not successful. This explains why people suffering from allergies sneeze more often, since the allergen they are trying to expel is still around. Other people who routinely sneeze many times in a row may just not have forceful sneezes.

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