The Sneeze Reflex

The Science of Sneezing

Sneezing is your body’s powerful way of protecting your airways from harmful irritants and getting rid of things that can make you sick or cause inflammation.

• A sneeze starts when something irritating — like dust, pollen, or pepper — enters your nose.
• Special nerve endings detect the irritant and send signals to the sneeze center in the brainstem.
• The brain then sends signals that prepare your body to remove the irritant forcefully.
• Air is forced out of your lungs at high speed — up to 100 miles per hour — to blow out the irritant.

Why and How We Sneeze?

Your body uses sneezing to defend itself and keep your nose clear.

• Sneezing is often caused by allergens (like pollen or pet dander), infections (like colds), or irritants (like smoke or perfume).
• Even sudden bright light can trigger a reflex sneeze in some people — this is called the photic sneeze reflex.
• Sneezing involves many muscles, including the diaphragm, chest, throat, and even the eyelids.
• We automatically shut our eyes when we sneeze because the reflex signal from the brain activates multiple facial muscles, including the ones that control blinking.

Fun Facts

Here are some interesting facts about sneezing:

• You can’t sneeze in your sleep because the sneeze reflex is turned off.
• Cats and dogs can sneeze too — it can be a sign of irritation or even excitement.
• Some people sneeze after eating — this rare reflex is called gustatory rhinitis.
• Your brain actually “decides” when a sneeze is strong enough to fire!

Review

Let’s quickly recap what we learned about sneezing:

• What part of the brain controls sneezing? Brainstem
• What is sneezing trying to remove? Irritants
• What are the main muscles that help you sneeze? Chest & Throat
• What is a sneeze caused by sunlight called? Photic Sneeze Reflex