Ah-CHOO! 7 Tickling Facts About Sneezing
Everyone knows the feeling: it begins with that insidious tickle in the back of your nose, then comes the gasping intake of breath and the final, cathartic blast: a sneeze. Whether it's sickness, allergies or even just bright light, many things can trigger these violent expulsions of mucus and saliva. But why do humans and other animals sneeze? How far and fast do sneezes travel, and why do they sometimes come in sets? Here are answers to the questions you're itching to know about sneezing.
Sneezing is one of the body's natural defense mechanisms for expelling foreign invaders and protecting the lungs and other organs from contamination. The medical term for sneezing is "sternutation."
Many things can trigger sneezes, including common colds, allergens (such as pollen or pet dander), physical irritants (such as smoke or pollution), environmental particles (dust, mildew and mold), cold air or bright sunlight. Sneezes begin when respiratory epithelium, which is the layer of cells that line the nose, becomes irritated and triggers the ending of the trigeminal cranial nerve, which then tells the brain to initiate the sneeze reflex.
Sneezes expel air from the body at speeds of up to 93 mph (150 kilometers per hour), studies have shown. And researchers have found that sneezes may travel much farther than previously thought. High-speed video of a sneeze shows that the mucous spray can travel between five and 200 times farther by traveling as droplets in an invisible gas cloud than they would if they traveled as individual droplets.
The sneeze reflex triggers the body to contract muscles all over, from the eyelids to the sphincter. Why this occurs is a mystery, however. It could be because of how the nervous system is wired. One possibility is that the body associates protecting the nasal passages with protecting the eyes. In fact, 1 in 4 people sneeze in bright sunlight, known as the photic sneeze reflex, or by the cleverly contrived name, autosomal dominant compelling helio-opthalmic outburst, or ACHOO, syndrome.
Some people have compared the act of sneezing to an orgasm. While the two phenomena have some similarities, the comparison is mostly anecdotal. However, there have been reports of men and women who sneeze when they're sexually aroused, possibly because of crossed up wiring in the autonomic nervous system, researchers say. There does seem to be a connection — both the nose and the genitals contain erectile tissue. And some people develop stuffy noses during sex, a condition romantically referred to as honeymoon rhinitis.
From a delicate sniffle to an elephantine roar, sneezes come in many shapes and sizes. The reason comes down to differences in anatomy and self-control. One survey found that 45 percent of people say their public sneezes differ from their private ones, according to a representative for the allergy drug Benadryl.
Some people's sneezes seem to naturally come in twos, threes or longer sets. These "paroxysmal" sneezers may suffer from allergies, researchers say. Or, in rare cases, epilepsy patients may have sneezing fits. Most of the time, though, a series of sneezes comes from a personal tic, or an attempt to rid the body of a speck of dust.