The Surprising Science: What Makes Sneezes So Powerful?

September 28, 2025 •

2 min read

A single sneeze can expel thousands of droplets at speeds approaching 100 miles per hour. This surprising fact demonstrates the sheer force behind this common bodily function and begs the question: What makes sneezes so powerful?

Quick Summary

A sneeze's power comes from a protective reflex: a deep breath, pressure in the chest and lungs, and air forcefully expelled through a narrowed nasal passage to clear irritants.

Key Points

Pressure Build-up: Force comes from pressure in lungs and chest after deep inhalation.
Coordinated Muscles: Involuntary reflex coordinates diaphragm, abdominal, and chest muscles.
Airway Restriction: Tongue and palate narrow passage to increase speed and clear irritants.
Protective Mechanism: Powerful burst clears foreign particles from the respiratory tract.
Don't Hold It In: Suppressing sneeze redirects pressure, risking ear damage or ruptured blood vessels.

The Sneeze Reflex: A Coordinated Biological Explosion

The power of a sneeze stems from a complex physiological reflex. It begins when irritants in the nasal lining stimulate nerve endings, sending a signal to the brainstem's sneeze center. This triggers a series of involuntary muscle movements throughout the upper body to expel the irritant.

Building Pressure: The Engine of the Sneeze

The sneeze's force is generated by a significant build-up of pressure. An involuntary deep breath fills the lungs with air, followed by contractions of abdominal and chest muscles and the diaphragm, compressing the lungs and increasing pressure. The vocal cords also close, trapping air and further increasing internal pressure.

The Sudden Release: From Pressure to Power

The explosive force is released when vocal cords open, and the soft palate and tongue partially block the mouth, directing air through the nose. This accelerates the airflow, creating the sneeze's characteristic sound and speed.

Why So Much Force? A Protective Mechanism

Sneezes are powerful because they are a highly effective protective mechanism to clear irritants, allergens, and pathogens from the respiratory system. High-speed imaging shows the wide dispersal of droplets, highlighting the importance of covering sneezes to prevent germ spread.

Common Triggers for Sneezing

Allergens: Pollen, dust mites, pet dander.
Infections: Viruses and bacteria.
Environmental Irritants: Strong odors, smoke.
Bright Light: Photic sneeze reflex.
Sudden Temperature Changes: Rapid temperature drops.
Full Stomach: Snatiation (rare inherited condition).

The Dangers of Holding a Sneeze

Given the high pressures, holding in a sneeze is not advisable. The redirected pressure can cause injuries such as ruptured eardrums, damage to blood vessels, or, rarely, a collapsed lung. To avoid spreading germs, sneeze into a tissue or your elbow.


Feature	Sneeze	Cough
Trigger Location	Nasal cavity, upper respiratory tract	Larynx, trachea, lower respiratory tract
Mechanism of Force	High pressure from abdominal/chest muscles expelled through narrowed nasal passage	Primarily high intrathoracic pressure expelled through the mouth via sudden glottis opening
Purpose	To clear irritants from the nasal cavity	To clear irritants from the throat and lower airways
Peak Velocity	Up to 100 mph (160 kph)	Approximately 60 mph (96 kph)

For more information on the risks of stifling a sneeze, you can read expert insights on the topic {Link: Cleveland Clinic Health Essentials https://health.clevelandclinic.org/dont-stifle-that-sneeze-you-could-get-hurt}.

Conclusion: The Amazing Reflex

A sneeze is a powerful, protective reflex involving coordinated muscles and pressure to expel irritants.

Frequently Asked Questions

A sneeze can expel air at speeds of up to 100 miles per hour, generating a significant force to clear nasal passages.

Yes, holding in a sneeze is not recommended. The immense pressure can be redirected and may potentially cause injuries to your eardrums, blood vessels, or diaphragm.

Before a sneeze, your body takes a deep breath, and muscles in your chest, abdomen, and diaphragm contract to build up high pressure in the lungs.

Closing your eyes during a sneeze is an involuntary reflex. It’s thought to be an autonomic response to protect the eyes from the force and droplets expelled.

The volume of a sneeze can vary based on lung capacity, the size of a person's airways, and the amount of air inhaled. It can also be influenced by learned social behaviors.

No, you cannot sneeze while in a deep sleep state (REM atonia). The reflex pathway is temporarily suppressed. A person would need to be partially awake to sneeze.

Once the reflex is triggered, it's very difficult to stop. Some people have luck with pressing a finger firmly against the area just under their nose to disrupt the nerve signal, but it's not a guaranteed method.