Sneeze

A sneeze is a semi-autonomous, convulsive expulsion of air from the lungs.

Sneezing occurs when a particle (or sufficient particles) passes through the nasal hairs and reaches the nasal mucosa. This triggers the production of histamines, which reach the nerve cells in the nose, which then send a signal to the brain to initiate the sneeze. The brain relates the initial signal and creates a large opening of the nasal cavity. In certain individuals, sneezing can also be caused by exposure to bright light. This is called the photic sneeze reflex.

In recent years it has been shown that stifling or holding back sneezes can cause damage to the sinuses as well as the inner ear. This is due to the back flow of air pressure. The symptoms of this can include tinnitus, or reduced high frequency hearing, and in extreme cases, rupturing of the ear drum.

Sneezes spread disease by producing infectious droplets that are 0.5 to 5 µm in diameter. About 40,000 such droplets can be produced by a single sneeze.

Beliefs and cultural aspects
In 410 BC the Athenian general Xenophon gave a dramatic oration exhorting his fellow soldiers to follow him to liberty or to death against the Persians. He spoke for an hour motivating his army and assuring them a safe return to Athens until a soldier underscored his conclusion with a sneeze. Thinking that this sneeze was a favorable sign from the gods, the soldiers bowed before Xenophon and followed his command. Another divine moment of sneezing for the Greeks occurs in the story of Odysseus. Odysseus returns home disguised as a beggar and talks with his waiting wife Penelope. She says to Odysseus, not knowing to whom she speaks, that he will return safely to challenge her suitors. At that moment their son sneezes loudly and Penelope laughs with joy, reassured that it is a sign from the gods.

According to popular belief, especially in the Japanese culture, a sneeze without an obvious cause is a sign that someone is talking about you.

Onomatopoeia
Some common English onomatopoeias for the sneeze sound are "achew!", "atisshoo" and "achoo". The first syllable corresponds to the sudden intake of air, the second to the sound of the sneeze. In Cypriot Greek, the word is 'apshoo'. (This is also the name of a village, which is the cause of much mirth.) In French, the sound "Atchoum!" is used, and in Japanese, "Hakushou!"

Traditional responses to a sneeze
In English-speaking countries, it is common for at least one person to say "God bless you" (or more commonly just "Bless you") after someone sneezes. This tradition originates from the Middle Ages, when it was believed that when one sneezed, the heart stops, the soul left the body and could be snatched by evil spirits. Today, it is said mostly in the spirit of good manners and is usually followed by the sneezer saying 'Thank you'. Also, when the Scarlet Fever broke out for the first time, people would often die as a result. People then began saying God bless you, in the hope that they would survive.

In many cultures words referencing health or good health are used instead of "Bless you". The German word "Gesundheit" is occasionally said after a sneeze. In Spanish, one says "Salud," which means "(to your) health"; in Finnish language, "terveydeksi", which also means "to your health"; in Romanian one says "Sănătate!" ("health") or "Noroc!" ("Luck"). In Hebrew לבריאות — labri'ut or livri'ut — for (the) health. In Norway, Sweden and Denmark, one says "prosit", Latin for "may it advantage (you)". The appropriate response in Russian is "будь здоров(а/ы)," which means "be healthy." In Armenia, one says "առողջություն" (aroghjootyoon). In Turkish, "Cok yasa" which means "live long", which in turn is responded with "sen de gor" (you see too) indicating the person wishing them to live long see them live as long. In Arabic (Jordanian dialect) bless you is صَحة (Sahha) which has probably evolved from Sihha صِحة meaning health! Also, one may say Nashweh نشوة which means ecstasy. The response is either thank you (شكرا Shukran) or Tislam/ Taslam (in different accents)تسلم which means 'may you be kept safe'. In French, after the first sneeze, one says "à tes souhaits!" which means "to your desires". If the same person sneezes again, the second response is "à tes amours!", which means "to your loves."

The practice among Muslims is based on the Prophetic Traditions. Al-Bukhaari (6224) narrated from Abu Hurayrah that the Islamic prophet, Muhammad said: “When one of you sneezes, let him say, ‘Al-hamdu-Lillaah (Praise be to Allaah),’ and let his brother or companion say to him. ‘Yarhamuk Allaah (May Allaah have mercy on you).’ If he says, ‘Yarhamuk-Allaah,’ then let (the sneezer) say, ‘Yahdeekum Allaah wa yuslihu baalakum (May Allaah guide you and rectify your condition).’”

The Dutch usually say "gezondheid" (literally translated means health) or "proost" (which means cheers.