Why Does Light Help You Sneeze?


What’s the most common advice you get when you feel like sneezing? That’s right, at least one person tells you to look into the light. And most of the time, it actually works. In fact, it works so well that nearly 35% of the world population sneezes when looking at something bright – even if they didn’t feel like doing so before!


So how does it work?

First of all, if you thought this is normal, the answer is yes and no. The act of sneezing comes as a reflex of the brain which is triggered by bright lights, but it is, in fact, a syndrome: Autosomal Dominant Compulsive Helio-ophtalmic Outbursts of Sneezing or, simply said, ACHOO. So we obviously know the symptoms, but what’s the actual connection between light and sneezing?

This has been a dilemma for centuries. Aristotle thought that it was because of the heat which came from the sun, Francis Bacon said that our eyes watered and caused an irritation – but, as it turned out later, none of these theories is valid. However, the actual explanation is just as simple.


The trigeminal nerve is responsible for any movements or sensations of the face, particularly the nose (a tickling feather, dust, pepper or hair especially in the nose). Although they’re not directly linked, this nerve is located very close to the optical nerve, so when you suddenly look into a very bright light, the optical nerve creates a specific signal. It’s believed that the trigeminal nerve interprets this signal wrongly and it makes us sneeze.

Weird as it may seem, ACHOO is a genetic condition so if you suffer from it, your kids will probably have the same symptoms. While it may, in fact, be harmful depending on your job such as that of a pilot, sneezing from time to time is healthy for the human body and heart.


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