What happens to our body during a sneeze?

There's nothing more common than sneezing, so we don't pay much attention to it when it happens to us. It's only when its frequency increases throughout the day that we wonder if there's really something wrong with us.

Why do we sneeze?

The simplest explanation is that our body's automatic, involuntary reaction occurs when our nose detects something that bothers it (e.g. an allergen) and will immediately try to get it out. However, there are other reasons why this happens.

"Sneezing is one of our body's most common responses, yet we often don't take the time to think about how and why it happens," explains Tim Mynes, an emergency physician from Virginia, adding that "it's essentially an involuntary release of air that helps the body remove irritants, such as allergens, odors, and dust, from the nose and throat."

Of course, as the doctor says, this activity will be strongly noticeable when we are faced with something that causes us allergies or a cold.

At the same time, in addition to dust, soot, nasal sprays and sudden exposure to light, a trauma to the nose and inhalation of cold air can lead to sneezing. “We can sneeze when we inhale cold air because the nasal mucosa will dry out and crack, causing the same reaction to the nerves in the nose as dust,” says the doctor.

In fact, according to a 2019 study published in Scientific Reports, it was observed that sneezing triggered by bright light, which is known as reflex sneezing, is an inherited trait. More specifically, in the research sample of more than 3,400 people in China, a link between reflex sneezing and a specific gene was identified.

What exactly happens when we sneeze?

Although it may seem like we are causing the sneeze, in reality our body goes through several steps until it reaches this reaction.

As Dilraj Kalsi, a doctor and founder of a medical center in London, says, “the sneeze reflex begins with irritation of the nasal mucosa, as sensed by the cilia of these cells. These receptors send signals via the trigeminal sensory nerves to the sneeze center in the lateral spinal cord.”

Then, as Dr. Kalsi points out, two different nerve signals are activated, one in the muscles of the pharynx, larynx, and respiratory system, causing sneezing, while the other, through the parasympathetic nerves, increases nasal secretion and tears.

On the other hand, just before a sneeze, the body prepares itself as the chest muscles compress the lungs while the vocal cords close, says Dr. Mynes.

 "When the vocal cords reopen, air is forced into the airways and through the nose at high speed. The eyes close and the diaphragm moves upward as the chest muscles contract, releasing air from the lungs," the doctor explains.

These droplets released from the nose and mouth are the allergens that have been exhaled, however they can contain viruses and germs, spreading them to other people. This is why scientists remind us that when we sneeze, we should cover our mouth and nose by sneezing into the inside of our elbow or into a tissue. If this is not possible, we should put our hand in front of it and immediately wash it thoroughly.