Why Do We Sneeze?

This and Other Common Sneezing Questions Answered

Outdoor portrait of sneezing boy
The truth, myths, and legends about sneezing. Anna Pekunova/Getty Images

 

While seldom addressed in medical circles other than as one of severe symptoms experienced by those with hayfever, sneezing has been defined in many ways in non-medical circles. You may have heard that when you sneeze you are the closest you'll ever get to death without dying. Or perhaps you've heard one of the other myths or legends surrounding sneezing. What can you believe?

What Is Sneezing?

Sneezing used to be thought of as a means for the body to drive out evil spirits.

But today, we know that the sudden forceful expulsion of air through the nose and mouth is caused by irritation of the mucous membrane. Functional and less scary, but more, well, boring? Here's everything you've ever wanted to know about sneezing—plus a few things you probably didn't even know you wanted to know.

What Causes Sneezing?

Sneezing is your body's way of removing an irritant from your nose. When something's causing a tickle or itch, your brain sends a signal to get rid of the invader as soon as possible, in the form of a sneeze. Your abdominal muscles, chest muscles, diaphragm, vocal cord muscles, throat muscles and eyelid muscles are all recruited to help you sneeze.

Common causes of sneezing include:

  • Nasal irritants, such as dust, pepper, powders and pollens
  • Viral infections, such as the common cold
  • Corticosteroid inhalation
  • Exposure to sunlight (this is known as the photic sneeze reflex)

Sneezing Myths and Legends

Sneezing has fascinated people throughout history. There are many myths, legends, and misunderstanding about sneezing. Some of these include:

  • What is the force of a sneeze? - A popular myth, based on old science, is that a sneeze can leave the body at a speed of about 93 miles per hour. However, more recent research shows that a sneeze actually leaves the body at about 10 miles per hour, which is about the same force as a cough.
  • What is the longest sneezing attack? - According to common folklore, a 12-year-old in England named Donna Griffiths holds the longest attack of sneezing on record. Apparently, she sneezed for over 977 days between January 1981 and September 1983. At first, she sneezed every minute, but as the days moved into weeks and years her sneezes occurred about every five minutes.
  • Does the heart stop when we sneeze? - There is a common belief that the heart stops whenever we sneeze. It does not, although it can feel like your heart changes beat. Positive pressure is created in the chest when we sneeze (or cough), and that can momentarily alter the forcefulness with which your heart beats.

Is Sneezing Life Threatening?

There have been some misconceptions that sneezing might be life threatening, however there are no recorded cases of anyone ever dying from letting out a sneeze. However, because you reflexively close your our eyes during each sneeze, it is possible that an ill-timed sneeze while driving could mean you fail to notice the car in front of you, or that the light has turned red. So, sneeze carefully!

Is It Safe to Hold in a Sneeze?

Since sneezing is a protective reflex—we sneeze to get rid of an irritant that entered our system—it doesn't seem healthy to hold in a sneeze.

At the same time, the consequences you may have heard aren't true. Stifling a sneeze won't cause a blown out kidney or a stroke.

However, stifling a sneeze during a cold may cause a middle ear infection because any infected discharge is kept in the body and could travel further inside through the ear. Also, a particularly powerful stifled sneeze could damage eardrums.

Photic Sneeze Reflex

If you've ever sneezed upon going outside on a bright and sunny day you are not alone. Sneezing in response to sunlight has been coined the photic sneeze reflex, solar sneeze reflex, or light sneeze reflex. If you sneeze in response to sunlight you may be interested to learn that the sneeze reflex is not a simple reflex, or what we usually refer to as a reflex.

Classical reflexes take place at either the spinal cord or the brainstem. In contrast, sneezing in response to sunlight involves areas in the cerebral cortex of the brain, or what is considered the higher functioning part of the brain.

Pathological Sneezing - Photic Sneeze Reflex to the Extreme

As with most medical symptoms, the act of sneezing can also be pathologic in that it may occur at times when it does not serve a purpose. In a syndrome known as Compelling Helio-Opthalmic Outburst Syndrome, also called the photic sneeze reflex gone bad, people have an outburst of sneezing in response to exposure to intense light. While not usually enough to be terribly bothersome, this syndrome has been reported in the literature going back to ancient Greece.

Do People Sneeze While Sleeping?

It sounds like few people recall ever sneezing while asleep, or at least waking up from a sneeze, and experts who study sleep agree. While we aren't certain why people don't usually sneeze while asleep, we will likely learn more as our knowledge about sleep and the brain increases.

Sneezing and Leaking Urine

As with coughing and other activities which increase abdominal pressure, sneezing may be feared by those who have stress incontinence. It's not just pregnant women who dread sneezing due to the trickle that can occur. If you know what we are talking about, this might be a good time to read up on—and start practicing—kegel exercises.

Sneezing and Seasonal Allergies

Certainly, sneezing is no laughing matter for those who suffer from seasonal allergies (also called allergic rhinitis or hayfever.) Of the possible causes for sneezing, the pollen count in the air is a common one for allergy sufferers. Vasomotor rhinitis, or non-allergic rhinitis can cause irritating sneezes as well. If you are coping with either of these conditions, take a moment to learn about the treatment options—treatments that will hopefully leave you in a position where others don't have to say, "bless you," or at least not because you sneezed.

Why Do We Say Bless You?

At least 1,500 years ago, people believed that the soul temporary left a body during a sneeze. This means that the body would be left temporarily without a soul, leaving it vulnerable to being occupied by the devil. Saying "God bless you" was meant to safeguard the sneezer from having this happen to them while their soul was out of their body.

Who would have thought there would be so much to learn about sneezing?

Sources:

Garcia-Moreno, J. Photic Sneeze Reflex or Autosomal Dominant Compelling Helio-Opthalmic Outburst Syndrome. Neurologia. 2006. 21(1):26-33.

Langer, N., Beeli, G., and L. Jancke. When the Sun Prickles Your Nose: An EEG Study Identifying Neural Bases of Photic Sneezing. PLoS One. 5(2):e9208.

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