Science

Why do we sneeze?

Everyone in the room is quiet. Perhaps you’re at a fancy function. Maybe it’s the most dramatic scene of a movie. Either way, you feel a tickle in your nose and the imminent premonition that you’re about to ruin the mood. And there’s nothing you can do to stop it. Sneezing has been creating disturbances for as long as humans have existed. It’s just one of those annoying aspects of life that we have to deal with. But why do we do it? And is there anything we can do to prevent it?

Sneezing as a function

Man in blue shirt sneezing into a handkerchief
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The primary purpose of a sneeze is to remove irritants from the nasal passage. These irritants include dust, dirt, pollen, smoke, or anything else that could possibly get stuck in there. Blowing it all out is the best idea your body has to clear it.

As soon as your brain sends the command to sneeze, your body has to prepare for the violent explosion that’s about to occur. Automatically, your eyes shut, your tongue moves to the roof of your mouth and your muscles will contract to brace for the pressure. Everything happens in a matter of seconds. Your tongue redirects the majority of the air through the nasal passage but still leaves some air to come out of the mouth, like a pressure relief valve. The sudden force of air clears out anything and everything that shouldn’t be in your nose.

Sometimes sneezes seem to come in pairs or more. Some people even have a specific number of sneezes that they produce each time. This is thought to be because the irritant was not expelled during the first or second sneeze, and the body just had to keep trying. If someone sneezes three times, every time, their sneezes might not be as powerful as a single-sneezer’s is, and it requires three attempts to get rid of the irritant.

Other benefits of sneezing

Sick woman in blue holding a cup of tea and sneezing into a tissue
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If sneezing is to get rid of debris, then why do people sneeze more when they’re sick? Sneezing actually plays an important role in fighting the spread of bacteria as well! The body’s natural reaction to infection is to produce mucus in an effort to trap the bacteria. Once trapped, it’s time to get rid of it. Cue your nose! Sneezing is the most efficient way to expel mucus from the body. Now, whether it’s a good or bad way of doing things depends on which side of the sneeze you’re on; it’s also the most efficient way to spread bacteria. Remember to cover your nose!

Reset the nasal passage

Close up of woman's face showing the nose and sinuses
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Even when there aren’t irritants or bacteria present, your nose produces mucus to catch potential irritants before they can get to your lungs. Sometimes, through normal production, the nasal passage gets too full and needs to be reset. Whenever you get a random sneeze that seems to be out of nowhere, it’s most likely just to reset your nasal passage.

Odd reasons to sneeze

Man standing outside and sneezing in the bright sunlight
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Sneezing is still somewhat of a mystery, and there are some causes that don’t seem to make much sense. About one in four people sneeze when they look into a bright light. This is called a photic sneeze reflex, and it’s an inherited genetic trait. The leading theory is that certain stimulation of the optical nerve causes the same sensation in your brain as irritation in the nose, but the true cause still eludes researchers.

Can it be stopped?

Man in striped shirt standing outside with a tissue, preparing to sneeze
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Much like a train wreck, once the action has started, it can’t be stopped. The best way to avoid sneezing is to avoid your triggers. If you’re allergic to cats, stay away from cats. Otherwise, you better have tissues on hand. Everyone has different triggers, so the only way to discover what makes you sneeze is through experience.

Many people pinch their nose right before a sneeze to stop the action. While it may stop the sound, it also doesn’t allow the sneeze to do its job. All the irritants and bacteria that were supposed to be removed are still in your nasal passage, ready to do harm. It happens for a reason, so it’s a good idea to just let your body do its job.

There are also plenty of old wives’ tales claiming that doing odd things like saying “pickles” or tickling the roof of your mouth with your tongue will distract you and stop the sneeze. There are no scientific facts to back these up, but if it works for you, by all means keep it up!