Why Looking at the Sun Makes You Sneeze — The Strange Reflex Millions Have

Have you ever noticed an unexpected sneeze when you step outside into the sunlight? You’re not alone in this intriguing phenomenon. What triggers this reaction, and is there a hidden link between sunlight and that sudden urge to sneeze?

What Is the Photic Sneeze Reflex?

Let’s start with the basics: the photic sneeze reflex. It’s a fancy name for a surprisingly common phenomenon. In fact, up to 35% of people experience it, according to medical researchers.

• The reflex causes sneezing when you’re exposed to bright light, especially sunlight.
• It’s hereditary—if you sneeze at the sun, there’s a good chance someone in your family does too.
• Some people call it “sun sneezing,” but doctors refer to it as Autosomal Dominant Compelling Helio-Ophthalmic Outburst (ACHOO) syndrome. (Yes, really!)

Why Does Sunlight Make You Sneeze?

Here’s where things get interesting. Why does a burst of sunlight trigger a sneeze for some people and not others? Scientists have a pretty good idea, though it’s not fully understood.

• When sunlight hits your eyes, your optic nerve sends a signal to your brain.
• In people with the photic sneeze reflex, the brain seems to “mix up” this signal with the nearby trigeminal nerve, which controls sneezing.
• The result? Your brain interprets the sudden light as an irritant, like dust or pepper, and triggers a sneeze to “clear out” your nose.

It’s not dangerous, but it sure is surprising! Have you ever tried sneezing on command just by looking at a light? (It works for me almost every time.)

Is It Just the Sun?

You might be wondering: does it have to be the sun, or can any light cause this reaction? Great question!

• Most people with the reflex report sneezing mostly in response to bright sunlight.
• However, some also sneeze when exposed to other intense lights, like camera flashes or bright indoor lights after being in the dark.
• The common factor? A sudden, strong change in light intensity.

Is It Harmful?

Don’t worry—the photic sneeze reflex isn’t harmful. In fact, it’s so common that many people don’t even realize it’s unusual! The general medical consensus is that it’s a benign quirk of your nervous system.

• It doesn’t mean you have allergies or an underlying condition.
• Some people use it to “force” a sneeze when they have that annoying tickle in their nose!
• The only real danger? Sneezing at the wrong time—like while driving or operating machinery. So, it’s wise to be cautious in those situations.

Why Do Some People Have It, and Others Don’t?

Turns out, photic sneezing is genetic. If you’re a sun-sneezer, you probably inherited it from a parent. Studies suggest it follows an autosomal dominant inheritance pattern, meaning just one copy of the gene is enough to experience the reflex.

• About 1 in 3 people have at least some tendency to sun-sneeze.
• It affects men and women equally.
• Some families even joke about their “sun sneeze gene!”

What Should You Do If You Have It?

For most of us, photic sneezing is just a quirky fact to share at parties. But if it gets in the way (like making you sneeze while driving), consider these quick tips:

• Wear sunglasses when going outdoors—especially when moving from dark to light environments.
• Avoid staring directly at bright light sources, like the sun or floodlights.
• If you feel a sneeze coming on at a risky moment, try to shield your eyes or close them briefly.

Fun Facts About Photic Sneezing

This reflex has fascinated scientists and laypeople alike for centuries. Did you know Aristotle wrote about people sneezing when looking at the sun nearly 2,000 years ago? And there’s even speculation that ancient warriors used it to their advantage before battle (though, take that with a grain of salt!)

• Some cultures have folk remedies for “sun sneezing.”
• The world record for most sneezes triggered by sunlight? No official record, but let’s just say, some people can’t stop at one!
• Even pets may sneeze at sudden bright lights, but it’s much rarer than in humans.

So next time you step out into the sunshine and let out a big achoo, just remember—you’re in good company. Weird? Maybe a little. Harmless? Totally. And now, you know the science behind that sun-powered sneeze!