Do your sneezes come in pairs? Or threes? For some people it's ten in a row! Why is this? Researchers have discovered it's because the sneezes are not powerful enough to do their intended job of ridding irritants in the nose. That's why people with disorders such as sinusitis are frequent sneezers.

We sneeze when a chemical or physical irritation enters and triggers the tissue lining our nose called the nasal mucosa. The signal is transmitted to the sneezing center in the brain. When enough nerves are stimulated, we sneeze. The speed estimated at a sneeze's top end is quite remarkable - 950 feet per second, which is about eighty five percent the speed of sound! Yet in people who sneeze a lot, their sneezes don't come near this and they're unable to reboot the environment in the nose.

Researchers discovered this by studying cells from the noses of mice, how well they cleared mucus and responded to simulated sneezes. They replicated some of the experiments in people and compared the nasal tissue of sinusitis patients with healthy tissue. Sinusitis is an inflammation of the nasal passages and those with the disorder did not respond to sneezes the same way as those with healthy tissue.

But not all sneezes are to rid the nose of irritants. One disorder called photic sneeze reflex is uncontrollable sneezing when the person is exposed suddenly to brilliant sunlight. Adolescent girls can sneeze for months and are treated through psychology. In some men and women, thoughts of sex or an orgasm can trigger sneezing, which could be embarrassing.

So we're merely on the edge of discovering all the reasons behind sneezing. Amazing how something we all do can remain so mysterious.