Every person must have sneezed, did not?. Then you know what really happens when we sneeze?.
First we need to know what it sneeze?. Sneezing is a semi-autonomous air discharge which occurs with hard through your nose and mouth. This air can reach the speed of 70 m / sec (250 km / h). Sneezing can spread the disease through the grains infected with the diameter of water between 0.5 to 5 μm. Approximately 40 000 grains of water as it can be produced in a single sneeze. Here is why you all should use a tissue when sneezing to prevent water-water containing the disease does not spread everywhere.
Then why do not we sneeze would close my eyes again?. Because there are nerves in the nose and eyes were actually interrelated, so that when we sneeze, then our eyes will be automatically closed. This is to protect the tear ducts and blood capillaries that are not contaminated by bacteria coming out of the membrane of the nose. At the time we sneeze, the reflex muscles in our faces became tense, the heart will stop beating for a moment. Immediately after sneezing then would come back again beating heart beating again alias.

Causes sneezing:
1. The incoming air stream will pass through the nasal cavity nasal mucous membrane-covered, if the mucous membrane was exposed to irritant substances or allergens will arise sneeze.
2. Arising from the presence of inflammation (rhinosinusitis), foreign bodies, viral infections, or allergic reactions.

The reaction caused by the Sneeze:
Symptoms of allergic reaction,
1. Sneezing.
2. Itchy nose.
3. Cold liquid.
4. Nasal congestion.

Sneezing actually useful to keep your nose clean, sneezing happens repeatedly expected to help clean-up effort in the nasal cavity.

Heart stopped beating when we sneeze.
Some students from a university in the United States to make research about this sneezing. They want to know why people give thanks and pray for each other during a sneeze. From the result, apparently at the time of the human heart stopped beating sneezing zero point fraction of a second. And we know if the heart is vital for human organs, and therefore you should cover your mouth when sneezing so viruses are not spread.