UNMC News

The science behind sneezing

Why sneeze? What's a sneeze uncovered in this column by Michael Huckabee, Ph.D.

Some people have the warrior sneeze that sounds like a call to battle, and there are those with the fairy princess “achoo” that squeaks out. Whatever size belongs to you, the fall allergies are out and sneezin’ season is here again. Omaha recently made its mark, ranking 13th in the list of cities with the most sneezing. Here are some little known facts about the universal experience of sneezing.

Why sneeze? Expelling contaminants that enter our bodies through the nose is the original goal of a sneeze, but this reflex often gets confused. The trigeminal nerve, which provides sensation to our face and innervates our jaw muscles, is wired to pick up any irritation inside the nose, such as pepper, pollen, dust, or molds. That makes sense, but then there’s other sneezes. Nearly one in four people sneeze when looking directly at the sun or any bright light (the photic sneeze). Some people sneeze after sex, some after plucking an eyebrow, others when experiencing a full stomach. The science behind those sneezes continues to be investigated, but answers are elusive.

What’s in a sneeze? It’s been estimated that 40,000 particles are expelled in the typical sneeze, but who’s counting? It’s more important what those particles are. In a now classic study from the late 1940s, researchers asked 48 individuals who were known carriers of group A streptococci (the bug that causes “strept throat”) to come sneeze in their laboratory. Devices were set out to catch the expelled bacteria. Eighty percent discharged large and heavy droplets containing bacteria which fell rapidly 1.5 feet from the sneezer. However, one participant (our warrior sneezer) had bacteria collected 9.5 feet away.

Can’t stop. While many people may have a series of several sneezes in a row, there are rare cases of intractable sneezing. These people, sometimes children, sneeze incessantly for weeks to months and the medical literature documents more than 50 cases. Each one stems from a psychological condition and treatment success has been achieved with biofeedback and relaxation exercises. For the rest of us, making the trigeminal nerve focus on something other than the sneeze may help stop it. That means such techniques as stretching the nose, pinching the skin below the nose or between the eyebrows, or clenching the teeth to tighten the jaw muscles may work.

Covering the sneeze. Let’s first address the dangers of the plug-your-nose technique. Pinching the nose closed only increases the internal pressure of the sneeze, and reports of popped blood vessels in the eyes, brain and chest are reported. So keep the nose open. Yet, getting the spray covered can be a trick. Many experts recommend we should sneeze into our elbows, which may reduce the spread better than the cover-your-mouth rule. The goal is to capture the sneezed contents, and a well-placed hanky will work fine. Immediate hand washing is a must if we catch the sneeze in our palm. If you choose the elbow, make sure your nose is sufficiently tucked into the bend.

Through world-class research and patient care, UNMC generates breakthroughs that make life better for people throughout Nebraska and beyond. Its education programs train more health professionals than any other institution in the state. Learn more at unmc.edu.

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Contact

Vicky Cerino
UNMC Public Relations
(402) 559-5190
vcerino@unmc.edu