6 facts about sneezing

We all sneeze sometimes – some of us more often or louder than others. Sneezing is a natural reaction, a reflex that is triggered when nerve endings inside the mucous membrane of the nose are stimulated. Sneezing helps clear out our nose or airways. It's a way of protecting the body from harmful or irritating substances. What is sneezing exactly? What happens in your body when you sneeze? What makes you sneeze? And what can you do to prevent sneezing?

1. What is sneezing?

Sneezing is the body's natural reaction to irritants inside the nose. A sneeze is usually triggered by an irritation in the nose, which is sensed by the trigeminal nerve, a cranial nerve responsible for facial sensation and motor control that carries the information back to the sneezing centre in the brain. This region then initiates the motor phase of the reflex, resulting in a sneeze. Just before you sneeze, pressure builds up in your lungs, causing you to inhale deeply. Then the laryngeal valve and the vocal cords close off the lungs, so that the air cannot get out temporarily. The expiratory muscles, which include your diaphragm, rib cage muscles and abdominal muscles, contract. This causes an explosive blast of air exiting the nostrils and lungs: a sneeze.

2. What happens when you sneeze?

Amazingly, a sneeze can travel up to 165 km per hour. When you sneeze, bacteria and viruses that are in your nose are released. We all know that if you don't sneeze into your elbow or a handkerchief, these organisms can spread rapidly from one person to the next. Colds and the flu, or other viruses, are spread by germs from coughs and sneezes.

3. What makes you sneeze?

A sneeze is most commonly caused by irritation of the nasal mucosa. That irritation can be due to any number of things. It can be caused by a hypersensitivity (allergy) to certain substances. Hay fever is an example of this type of allergy. It also be triggered by particles in the air or scents. House dust is a major cause of sneezing. Pepper and perfume also cause people to sneeze. Sneezing can also be a symptom of the common cold. The viruses that cause a cold affect the lining of the nose, causing it to become hypersensitive.

4. What can you do to induce a sneeze?

You're probably familiar with the annoying feeling you get when you need to sneeze but simply can't. To make yourself sneeze you can try looking upward toward a bright light. (Be careful not to look directly at the light source.) The change in light from dark to light transmits impulses to the sneeze-invoking centre in the brain via the optic nerve. This further activates the sneeze reflex, which makes the sneeze come out.

5. What can you do to stop a sneeze?

There are certain times when it’s really inconvenient to sneeze. For example, at places like lectures and concerts, or when you're driving or talking to someone. You can stifle a sneeze by pinching your nose or putting a finger under it when you feel a sneeze coming on. This can help stop the sneeze reflex. Blowing your nose can also help blow out the irritant. Don't wait too long though. Once a sneeze starts, it's almost impossible to stop it.

6. Why am I sneezing so much?

Sneezing is a natural reflex of the body that helps you get rid of the irritants in your nasal passage or airways. So in most cases, sneezing is useful, which is why it’s better not to hold it in. Sneezes are extremely forceful. If you block the release of this pressure by trying to hold in the sneeze (for example by closing your mouth or pinching your nose) it can cause a rupture of your eardrums, or in severe cases, even rupture blood vessels. Obviously, you don't want that to happen.

Sneezing is harmless

In most cases, sneezing is harmless and not a cause for concern. Usually, it will stop by itself. If sneezing is caused by a cold, you can use a nasal spray. If you're sneezing because you are hypersensitive to a certain substance, there are medications available that can help reduce hypersensitivity (antihistamines).

Some people are more prone to sneeze attacks than others. Is your sneezing becoming a problem? Perhaps a doctor's consultation at Dokteronline can help.
If you cannot stop sneezing and you don't have a cold, then it is probably worth getting an allergy test. Talk to your GP for more information.