What Really Happens When You Sneeze: Health Benefits, Science & Myths
Your body’s sudden burst of air expels irritants and signals a healthy immune response.
We have all experienced it: that sudden itch, the quick inhale, and then the unmistakable explosion—sneezing. While it may seem like just another bodily reflex, sneezing is an incredibly complex process involving your nose, brain, respiratory muscles, and immune response. In this in-depth guide, we’ll uncover the science behind sneezing, its critical role in protecting your health, common triggers and reflexes, and—critically—why you should never hold in a sneeze.
Why Do We Sneeze? The Body’s First Line of Defense
Sneezing, scientifically termed sternutation, is far more than a simple annoyance. It’s one of the body’s most efficient ways to expel irritants, pathogens, and foreign particles from your nasal passages. According to Dr. Satish Govindaraj, director of rhinology at Mount Sinai Health System, sneezing starts with irritation in the nasal lining, which sends signals through your nerves to trigger a powerful cleansing response.
- How it starts: The delicate mucous membranes in your nose detect: pollen, dust, viruses, bacteria, smoke, or other irritants, setting off the sneeze reflex.
- Mucous as a filter: The mucous in your nostrils traps dirt and bacteria, which the stomach later digests, neutralizing many pathogens. However, when irritants overwhelm this system, a sneeze is triggered.
- Immune response: Sneezing is both a mechanical expulsion and a part of your immune defense. The goal: eject infectious agents quickly.
The Anatomy of a Sneeze: What Happens During a Sneeze?
A sneeze involves more than your nose. It’s a coordinated event starring your nerves, brain, throat, chest, and even your eyes! Here’s what unfolds in a split second:
| Step | Action | Bodily Feature |
|---|---|---|
| 1 | Irritant detected by nasal mucosa | Nose/Nasal lining |
| 2 | Nerve signal sent to brain stem via trigeminal nerve | Trigeminal nerve/brain stem |
| 3 | Chain reaction activates facial, chest, throat, and eyelid muscles | Multiple muscle groups |
| 4 | Soft palate & uvula lower, tongue rises to seal mouth | Mouth, tongue, palate |
| 5 | Chest compresses, diaphragm pushes | Lungs, diaphragm |
| 6 | Eyes close reflexively | Ocular muscles |
| 7 | High-velocity air expelled—mainly through nose | Nasal & respiratory tract |
The result: up to 40,000 droplets containing mucus, saliva, and the original irritants blast into the environment at speeds that can exceed 100 miles per hour.
Why You Shouldn’t Hold in a Sneeze
It’s tempting to stifle a sneeze, especially in public. But experts warn that pinching your nose or clamping your mouth shut during a sneeze can backfire significantly. Suppressing that powerful urge can force the expelled air back into your head, sinuses, or even deeper into the body, sometimes causing serious injury.
What others are reading
- Potential risks include:
- Middle ear injury or ruptured eardrum
- Sinus ruptures
- Damage to blood vessels in the eyes or brain (extremely rare)
- Significant pain or infection risk
- Rather than holding it in, cover your nose and mouth with a tissue or elbow to prevent spreading germs to others.
As the soft palate and uvula move down and the tongue rises, the main exit for the expelled air and irritants is the nose. Blocking that route can disrupt the body’s finely tuned ejection system and, at worst, cause internal damage.
Common Sneeze Triggers: More Than Just Allergies
While allergens like pollen, pet dander, and dust constitute some of the most familiar sneeze triggers, many other factors can bring on a sneeze:
- Viral and bacterial infections: Especially during colds and flu.
- Environmental irritants: Smoke, perfumes, pollution, cleaning agents.
- Sudden temperature changes: Breathing in cold air or entering a cool environment.
- Strong emotions or excitement: Rare, but intense emotional reactions or sudden laughter can prompt sneezing in some people.
- Certain foods: Spicy foods, black pepper, or carbonation can trigger sneezes.
- Bright lights: Up to one-third of the population experiences the photic sneeze reflex, explained below.
Photic Sneeze Reflex (ACHOO): Sneezing at the Sight of Light
Have you ever felt a sneeze coming on just after stepping into sunlight? You may have something called the photic sneeze reflex, sometimes humorously labeled as ACHOO—short for Autosomal Compelling Helio-Ophthalmic Outburst. Science isn’t entirely sure why this occurs, but it’s most likely due to a cross-wiring in the brain where optic (vision) and trigeminal (nose sensation) nerve signals overlap.
- Roughly 35% of people are affected.
- Sneezing can be provoked by any bright light source—not just sunlight.
- This reflex is believed to be inherited genetically.
- There’s no danger associated with the photic sneeze reflex, but it can be surprising in situations like driving or operating machinery.
Benefits of Sneezing: How a Sneeze Protects You
Besides providing instant (albeit messy) relief, sneezing serves key protective functions:
- Removes airborne invaders: Viruses, bacteria, dust, and allergens are swept out of your nasal passages.
- Keeps nasal lining clean: Helps clear out dried mucus and debris.
- Prevents deeper infection: By ejecting pathogens early, sneezing helps avert infections in the lower respiratory tract.
- Signals healthy immune activity: Sneezing more during a cold or allergy season is generally a sign your body’s defenses are alert and active.
Is There a Right Way to Sneeze?
Though sneezing is involuntary, you can minimize its spread and protect others. Here are best practices, as recommended by immunologists:
- Sneeze into a tissue or your elbow—never your hands—to prevent germ transmission.
- Dispose of tissue immediately, then wash your hands thoroughly.
- Avoid stifling or suppressing sneezes.
- If you feel a sneeze coming on, step away from groups and turn your head.
Can You Stop a Sneeze?
Many claim they can thwart a sneeze by looking at a bright light, pressing under their nose, or pinching their nostrils. While you can sometimes suppress or delay a sneeze if you catch it very early, forcibly holding it in after it’s started can cause complications.
- Tricks to delay a sneeze include:
- Blink rapidly or look at a light (sometimes stops the sneeze reflex for photic sneezers)
- Press firmly on the bridge or underside of your nose
- Sniff sharply or blow your nose to clear irritants
- Say “pickles” quickly (may distract brain circuitry)
- If sneezing is frequent or severe, consult a doctor to identify underlying allergies or infections.
FAQs About Sneezing
Q: Why do I sneeze several times in a row?
A: Multiple sneezes may signal a persistent irritant or allergen and an active immune response. It’s common to sneeze two or three times in rapid succession if irritants remain present.
Q: Why do my eyes close when I sneeze?
A: The muscles controlling eyelids contract in what is essentially a reflexive protection, preventing any debris or expelled substance from contacting your eyes.
Q: Is it dangerous to hold in a sneeze?
A: Yes, forcibly stopping a sneeze by pinching your nose or holding your breath can result in air pressure being redirected to your sinuses, ears, or even eyes, rarely resulting in ruptured eardrums or blood vessels. It’s important to let sneezes happen naturally.
Q: Can you die from sneezing?
A: No, sneezing itself is not dangerous and is a normal bodily function. However, the myth that your heart stops when you sneeze is just that—a myth. There may be a brief alteration in heartbeat due to pressure changes, but nothing dangerous or life-threatening.
Q: What is the purpose of the “Achoo” sound?
A: The sound comes from the forceful rush of air and the reflexive touching of your tongue to the roof of your mouth, clearing the nasal passages. The sound is partly reflex, partly cultural, and varies globally.
Top Takeaways & Sneezing Etiquette
- Sneezing is a natural, protective reflex that helps keep germs and debris out of your body.
- Never forcibly block or stifle a sneeze—allow it to happen and direct it into a tissue or your elbow.
- Sneezing can be triggered by numerous stimuli: allergies, infections, cold air, bright lights, strong emotions, and certain foods.
- The photic sneeze reflex (ACHOO) is a genetic trait that affects over a third of people.
- Sneeze hygiene—use tissues, wash hands, and cover properly—prevents the spread of infectious agents.
When to See a Doctor
Occasional sneezing is healthy, but if you experience:
- Chronic, persistent sneezing interfering with daily life
- Frequent sneezing accompanied by fever, pain, or swelling
- Blood or unusual discharge from the nose
- Allergy-like symptoms not improved by common treatments
…consult an allergist or ENT specialist for proper diagnosis and treatment options.
Final Word: Embrace the Sneeze
Next time you’re caught mid-sneeze, remember: this loud biological reaction is your body’s way of safeguarding your health and flushing out unwanted invaders. So, respect the urge, follow sneeze etiquette, and let your body’s reflexes do what they do best.
References
- https://www.goodhousekeeping.com/health/wellness/a30357054/what-happens-when-you-sneeze/
- https://www.healthline.com/health/how-to-stop-sneezing
- https://www.uow.edu.au/media/2023/hello-hay-fever–why-pressing-under-your-nose-could-stop-a-sneeze-but-why-youshouldnt.php
- https://www.goodhousekeeping.com/health/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC8234364/
- https://www.medicinenet.com/11_facts_about_sneezes_and_sneezing/article.htm
- https://digital.library.cornell.edu/catalog/hearth6417403_1394_002
- https://www.discovermagazine.com/why-do-we-sneeze-46500
Similar Articles
Read full bio of Sneha Tete
