Do you really know? Why does looking at the sun make me sneeze?
Aug 11, 2025
Have you ever sneezed when stepping into bright sunlight? This peculiar phenomenon, known as the photic sneeze reflex, affects 10 to 35% of people. It’s not an allergy; instead, it's a harmless response triggered by sudden light exposure. The podcast explores the neurological mechanics behind this quirky reflex and whether it's advisable to suppress a sneeze. Get ready to uncover the science behind that unexpected sneeze!
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Photic Sneeze Reflex Is Common And Harmless
- Sudden bright light can trigger a photic sneeze reflex in 10–35% of people.
- Joseph Chance says it is congenital and harmless.
Nerve Cross‑Talk Triggers Light Sneezes
- Bright light activates the optic nerve and triggers squinting.
- Nearby trigeminal nerve input can be accidentally stimulated, causing a sneeze.
Sneezes Expel Air At High Speeds
- A sneeze forces air out through nose and mouth with high pressure.
- The body can expel air at speeds up to about 100 mph.