Blasting the nose clear
Why Do We Sneeze?
A sneeze is a reflex that clears your nose with a sudden burst of air.
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Step 1 of 5
Your nose lining is a filter.
A sneeze is what happens when the filter is overwhelmed Sticky mucus and tiny sweeping hairs catch dust, pollen and microbes before they reach your lungs. Sneezing is the emergency clear-out.
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Step 2 of 5
Irritation triggers a reflex.
The brainstem runs this one. You are told about it, not consulted. Nerve endings detect an irritant and signal the brainstem, which fires a fixed sequence. You cannot really choose to sneeze or not.
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Step 3 of 5
It is a coordinated sequence.
Deep breath, closed throat, chest muscles squeeze to build pressure, then the throat opens all at once and the air blasts out.
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Step 4 of 5
The blast is genuinely fast.
Air leaves at up to 160 km/h, carrying thousands of droplets several metres. That is exactly why sneezes spread illness so well.
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Step 5 of 5
Bright light sets some people off.
About one person in four sneezes when stepping into sunlight. The nerve signals appear to cross wires — it runs in families.
Sneeze into your elbow, not your hand. Hands are the main route germs use to reach the next person.
The short version
A sneeze is an automatic high-speed blast of air that clears irritants from your nose — and spreads germs efficiently.
Try it yourself
Look at slow-motion sneeze footage. The cloud travels far further than almost anyone expects.