Why Do We Sneeze?

It's something us may do several times a day, often in quick succession. Many of us will do it much more frequently now that spring is here. “It” is sneezing, but do you know what's going on inside your head right before that round of “God bless yous”?

For the longest time, medicine held that sneezing was a mere reflex. It was enough to know that when irritants such as germs, dust, pollen, animal dander, or pollutants infiltrated the nose lining, the brain sent out a message to evacuate the contaminant.

But recently researchers from the department of otorhinolaryngology – that's head and neck surgery – at the University of Pennsylvania in Philadelphia delved a little bit more deeply into the question as to why we sneeze.

“Very little is known about the effects of sneezing on the cells within the nose and sinuses,” says Noam Cohen, MD, PhD, assistant professor of Otorhinolaryngology at Upenn and senior author of the report. “As a matter of fact, almost nothing is known about sneezing.  As an ear, nose, and throat physician who deals with problems of the nose, frequent sneezing is a very common complaint I encounter from my patients.  So we wanted to know: why do people with problems with their noses, such as the common cold, chronic sinusitis, or allergies, sneeze more than people with no problems in the nose or sinuses.”

Reporting in the Journal of the Federation of American Societies for Experimental Biology, Professor Cohen and his team concluded we need to reset our nasal environment every once in a while, and sneezing is how we do it. For the study, the researchers took cells from the noses of mice and watched how they cleared mucus. Then they replicated their experiments in nasal cells from humans with and without sinusitis.

“What we found was that the pressure force of the sneeze activates the process by which our cells clear mucus --  like rebooting or hitting ‘control/alt/delete’ on a computer,” Cohen said.  “Since nothing was known about the cells’ response to a sneeze, this was a novel finding.”

But some patients with chronic sinus issues do not reboot, and their body's response is to sneeze more often. Cohen believes that, with some more research, it might be possible to develop novel therapies (nasal sprays, irrigations or oral medications) that can help these people reboot their system and help them clear the infected and thick mucus.