Lots of things can make you sneeze. The flu, pollen (a.k.a hay fever) and even a feather tickling your nostrils. But to some, just looking at the sun can trigger an "ah choo!". Is this really true?
VERDICT:
TRUE
Around 25% of the world's population has something called the photic sneeze reflex (PSR) or the autosomal dominant compelling helio-ophthalmic outburst syndrome, otherwise known as ACHOO.
While the exact science behind PSR is still somewhat debated in the scientific circles, the general theory is that the nerves that are connected to the eyes and nose, in some people is tangled. So a bright light, like looking at the sun, could trigger a tingle in your nose, resulting in a sneeze.
Many theories have been proposed to pinpoint the underlying mechanism that results in PSR, such as optic-trigeminal summation, parasympathetic hypersensitivity, and parasympathetic generalisation. Try saying those words five times quickly. Gesundheit!
REFERENCES
https://www.livescience.com/health/why-does-the-sun-make-people-sneeze
https://link.springer.com/article/10.1007/s00221-024-06988-4
