Why does looking at the sun make you sneeze

The sun is something that everyone sees every day. Even if there are clouds on that day and the sun is blocked, the sun still exists. Some people will look up at the sun when the weather is good and the sunlight is not too glaring, but as soon as they look up at the sun they will start sneezing. Everyone knows that sneezing is usually a symptom of an itchy nose, so why do they sneeze as soon as they look up at the sun?

Why do people sneeze when looking at the sun?

Many of us have experienced this situation: we sneeze when we see the sunlight. Why is this? Let us understand how to explain this problem that has been bothering us for a long time.

When we sneeze, it is because the nasal mucosa is stimulated by foreign objects, and the brain tells the nose to expel the foreign objects and not let them stay in the nasal cavity. The nasal mucosa then transmits this sensory signal to the brain via the trigeminal nerve. The trigeminal nerve has three branches and is the fifth of the twelve cranial nerves. It is responsible for collecting sensations from the face, nose and mouth. It is also responsible for muscle movement control and is responsible for the nasal sneeze reflex. It so happens that on the way the trigeminal nerve returns to the brain, there is a nerve that crosses it. This crossed nerve is the optic nerve, which is the nerve that controls our vision and is the second branch of the cranial nerves. The optic tube of the eye will, of course, be stimulated by light and emit signals.

When sunlight enters the eye, the optic nerve is stimulated and transmits electrical nerve signals back to the brain. This electrical nerve signal is like a train, traveling along the optic nerve. When it reaches the intersection with the trigeminal nerve, the electricity emitted cannot help but be received by the trigeminal nerve. The trigeminal nerve stupidly receives the wrong electrical signal and transmits it back to the brain. The brain doesn't care where the signal comes from. Once it sees a signal, it must be that the nasal mucosa is irritated by foreign objects, so it must expel them! Then, the brain commands all the muscles in the chest, lungs, oropharynx, and nasal cavity to start taking deep breaths, and then exhale violently. This is a sneeze.

Therefore, sneezing when seeing the sun will not harm our body except that it may make us a little embarrassed sometimes, nor will it lead to some basic problems. This is why not many people specialize in studying this phenomenon, and therefore there is little knowledge in this area.