Aaa-choo! While your first thought might be to “Gesundheit!” your second might be to ask, “Where did that sneeze come from?”
Sneezing is a phenomenon that occurs in both humans and animals. It happens when your body forcibly expels air from your lungs through your nose and mouth.
Usually, sneezing happens when something infectious, such as a virus or bacteria, or irritant, such as an allergen or chemical, enters your nostrils. Your body uses sneezing as a defense mechanism to clear your nose of mucus — known as snot — and prevent foreign objects and particles from entering your airways.
Lydia Bourouiba and her lab at MIT study the physics of sneezes.
But sneezing can also occur in response to more unusual stimuli.
Chemicals like piperine or capsaicin found in foods like black pepper and chili peppers can irritate the nerve endings in the mucous membranes of your nose and lead to sneezing.
Another type of sneeze is psychogenic, meaning it’s caused by something more mental than physical. While not fully understood, researchers believe it occurs when a strong emotion triggers your brain to send a chemical signal to your nose that makes you sneeze.
And finally, about one in four people experience something called photosneezia, or a photic sneeze reflex, where light, especially sunlight, can trigger a sneeze.
Is it possible to sneeze without closing your eyes?
Despite a popular myth that sneezing with your eyes open causes them to pop out, it’s actually possible to keep your eyes open when you sneeze.
Closing your eyes during a sneeze is an autonomic reflex. This means that your body does it without you having to consciously think about it. Scientists believe that your body closes your eyes when you sneeze to reduce the chance of germs getting in.
It is possible to combat that reflex and deliberately keep your eyes open. But it might be better to keep them closed to avoid getting the germs you’ve emitted in your eyes.
Why do you make noises when you sneeze?
Some people sneeze very hard, while others sneeze more delicately.
The sound you make when you sneeze is the result of air escaping from your mouth or nose. In general, the more air you breathe in, the louder your sneeze will be. Like closing your eyes, breathing in prior to a sneeze is largely a reflex, but it can also be controlled consciously.
Some people even hold back their sneezes or “swallow” them, although health experts don’t recommend it because of the potential risk of injury. Some sneezes can be so powerful that they expel mucus at up to 100 miles per hour!
What is proper sneezing etiquette?
While sometimes sneezing is just a reflex, or the result of an allergy or chemical irritation, sneezing can also be a symptom of an infectious disease or upper respiratory infection.
If you tend to sneeze, it’s best to sneeze into a tissue or your sleeve to catch the germs that may come out with the air you’ve expelled. If you’ve sneezed with a tissue or touched your nose and mouth, good hand hygiene, such as washing with soap and water or using hand sanitizer, is especially important to prevent the spread of germs.
Whether you sneeze with your eyes open or closed, hard or soft, covering your mouth and nose when you sneeze and washing your hands for 20 seconds afterward can help others get sick.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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