Sneezing is a common occurrence that most individuals experience, especially those with hay fever. It is a reflex action designed to protect our bodies from irritants that enter our nasal passages. Interestingly, while sneezing is universal, each person’s sneeze can be quite unique. Sneezing is a reflex action that occurs outside of our conscious control, and it involves the expulsion of irritants from our noses. The force generated during a sneeze is remarkable, with pressure in the airways exceeding that of heavy breathing during exercise by more than 30 times. The speed at which a sneeze travels also varies, with estimates ranging from 5 meters per second to over 150 kilometers per hour.
The initiation of a sneeze occurs when sensory nerves in the nose are stimulated by various irritants, including allergens, viruses, bacteria, or fluids. These sensory nerves transmit this information to the brain, and when a certain threshold of irritant signals is reached, the sneeze reflex is triggered. The sneezing process typically starts with a deep breath and the build-up of pressure within the airways. This is followed by the contraction of the diaphragm and rib muscles, reflexive closing of the eyes, and a forceful exhalation. These phases of a sneeze are commonly known as the “ah” and “tchoo” phases. During the exhalation, the tongue is lifted to the roof of the mouth, effectively closing off the back of the mouth and directing the air mostly through the nose. This expulsion of air through the nose helps to flush out the irritants that triggered the sneeze. The sound “tch” that accompanies a sneeze occurs when the tongue reflexively touches the roof of the mouth.
The trigeminal nerves play a crucial role in the sneezing process. These nerves are the largest sensory nerves in the body and are responsible for transmitting sensory information from the face to the brain. This includes touch, pain, and irritation signals from the skin, nose, and mouth. Within each trigeminal nerve are thousands of individual branches, each carrying specific types of sensory information. These sensory nerves travel to the brain via the spinal cord, where they communicate with each other via interneurons. In the gate control theory of pain, these interneurons act as “gates” that either allow or block pain signals from reaching the brain. Nerves carrying pain signals instruct the interneurons to “open the gate,” while larger nerves carrying touch information can “close the gate” and prevent pain messages from reaching the brain. This mechanism explains why rubbing an injured area can reduce the sensation of pain. Studies have shown that stimulating the trigeminal nerves, such as through jaw movement, can also help alleviate tooth pain.
Various suggestions exist on how to stop a sneeze, such as pulling your ear, pressing your tongue to the roof of your mouth or the back of your teeth, touching your nose, or even inserting a finger in your nose. All of these actions aim to stimulate the trigeminal touch nerves and prompt the interneurons to “close the gate.” By doing so, the irritant signals are blocked from reaching the brain, effectively preventing a sneeze. However, if a sneeze has already been triggered and you find yourself in a situation where sneezing may be inappropriate, such as in a quiet setting, it may be best to let the sneeze happen. Attempting to suppress a sneeze by closing your mouth or nose can lead to a significant increase in airway pressure, potentially causing damage to your eyes, ears, or blood vessels. While the risks are generally low, severe consequences such as brain aneurysm, ruptured throat, and collapsed lung have been reported. Therefore, it is advisable to address the underlying causes of sneezing, such as allergies or irritants, to prevent the reflex from occurring in the first place. In situations where prevention is not possible, embracing your unique sneeze style and using a tissue to expel the irritants is the recommended course of action.
Sneezing is a fascinating reflex action that serves as a protective mechanism against irritants that enter our nasal passages. Understanding the intricate process involved in sneezing, from the stimulation of sensory nerves to the interplay between pain and touch signals, can provide insights into how we can control or prevent sneezes. While various techniques exist to try and halt a sneeze, it is crucial to consider the potential risks and consequences associated with suppressing the reflex. Instead, focusing on addressing the underlying causes of sneezing and embracing our unique sneeze styles can lead to a more comfortable and natural approach to dealing with this universal phenomenon.