This Is What Really Happens When You Sneeze

We bet you've never though about the anatomy of a sneeze.

sneezeKamil Macniak/Shutterstock

Simultaneously expressing itself as a solid, a liquid, and a gas, the common sneeze is one of nature’s grossest miracles. (Just check out these 12 weird facts about sneezing.) MIT researcher Lydia Bourouiba has 
a different name for sneezes, though: violent expiratory events. That’s also the title of a recent study in which her team analyzed sneezes, millisecond by millisecond, with a high-speed camera and sophisticated computer models. What did they find? There’s more to a sneeze than what you see in your hankie—and that could 
influence our understanding of the way diseases spread. Here’s a closer look at what scientists see when you say a-choo!

  1. Like a blast of bird shot, the initial “jet phase” 
of a sneeze lasts only milli­seconds but can send an 
estimated 40,000 droplets of various sizes scattering outward as fast as a car on a highway. (This is how far your sneeze really travels.)
  2. The largest droplets 
(illustrated in green) 
rocket out of the sneezer’s mouth and rapidly plummet under their own weight within a few seconds. 
Average distance traveled: 
3 to 6.5 feet.
  3. The cloud grows and slows as it pulls in 
air from the environment, 
carrying the smallest 
droplets up to 26 feet from their point of origin.
  4. In the “puff phase” of 
a sneeze (illustrated 
in red), a turbulent cloud 
of warm, moist air swirls through the air, carrying the sneeze droplets with it.
  5. Buoyed by the cloud, small droplets can 
easily stay airborne long enough to reach overhead vents (and thus anywhere 
in a building). It’s a big problem. But there’s a solution an arm’s length away: Cover sneezes with a sleeve or tissue, wash your hands regularly, and keep those germs to yourself.

For more on sneezes, diseases, and how the two are related, visit lbourouiba.mit.edu. And be sure to check out these 14 other bizarre bodily functions you just can’t control.

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Originally Published in Reader's Digest