A quarter of people sneeze when they look at sunlight. The phenomenon is probably hereditary. But what happens in the body?
I looked briefly at the sun, then felt a tingling sensation in my nose, followed by a sneezing fit. Have you ever wondered why some people sneeze when they suddenly look at bright sunlight? This phenomenon is called the “photic sneeze reflex.” Around a quarter of all people are affected by it. Whether you are a sun sneezer or not is probably genetically determined. What distinguishes these people from the rest of the world is not clear. However, researchers have a suspicion.
Sneezing when looking at the sun: what's the reason?
Aristotle is said to have asked himself why one has to sneeze more often when one looks at the sun. However, he saw the reason for this in the heat radiated by the sun. This thesis is now considered refuted. As early as 1950, a French scientist is said to have discovered that it is actually light that causes a quarter of people to sneeze, according to a report by
BBC Future
. Artificial light works just like sunlight.
Sun sneezing: what happens in the body?
To understand “photic sneezing,” it’s worth taking a look at why people sneeze in the first place. Sneezing is one of our body's involuntary protective reflexes. When you sneeze, the inside of your nose is cleared of dirt or foreign particles. If the nasal mucosa is irritated by a foreign body, this stimulus travels to the brain via the so-called trigeminal nerve. This sends a signal to the affected body parts. We breathe in deeply, hold our breath and shoot air explosively through the nasal cavity. Pathogens such as those caused by a cold or flu as well as dirt particles are thrown out of the body. So sneezing is a good thing. However, suppressing sneezes by holding your nose or closing your mouth can be unhealthy.
In people with “photic sneezing,” the trigeminal nerve is said to be close to the optic nerve. The trigeminal nerve, also called the “triple nerve,” has three branches: an ophthalmic branch, a lower jaw branch and the upper jaw branch. The latter also plays an important role when sneezing. If you suddenly look at the sun, in some people not only the eye branch is stimulated, but also the one that leads to the upper jaw, which causes them to reflexively sneeze. According to this theory, some kind of short circuit is responsible for sun sneezing.
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Another reason for “photic sneezing” could be that some people are more sensitive to visual stimuli, as stated in a publication (
Langer et al)
from the
Free University of Berlin
. However, none of these theories are considered certain.
“Photic sneezing reflex”: Is the phenomenon dangerous?
The “photic sneeze reflex” occurs primarily when one is suddenly exposed to light. But is sneezing in the sun dangerous? There are probably no health risks associated with this phenomenon. It's probably a harmless anomaly in our genetics. It only becomes dangerous if you are restricted by sneezing - so sneezing while driving can be dangerous. Driving through a tunnel, for example: The sudden change in light at the tunnel exit can be accompanied by a sneezing fit, which makes it difficult to concentrate.
This article only contains general information on the respective health topic and is therefore not intended for self-diagnosis, treatment or medication. It in no way replaces a visit to the doctor. Our editorial team is not allowed to answer individual questions about medical conditions.