Every time we breathe through our nose, thousands of tiny pieces of dust and other particles attempt to enter it. Our nasal hairs work as an air purifier, cleansing the air that enters of bacteria and other particles. A sneeze is our body's way of getting harmful substances (like bacteria, pollutants and viruses) out of our airway to protect us. While our own sneeze is there to protect us, someone else's sneeze may take us over the edge into sickness.

According to Len Horovitz, MD a specialist in respiratory illnesses at Lenox Hill Hospital in New York, all it takes is one sneeze to send well over 40,000 bacteria-filled droplets in your direction at about 100 mph. In that moment this sneeze alone may tamper with your immune system, but on the other hand, the sneezer doesn't even need to be present for you to pick up the germs.

The germs in these droplets are so hardy that they can survive for up to 24 hours, says Horovitz. This means that if someone sneezes in your office after you've gone home for the day, and then they use their germ-covered hand to open the office refrigerator, office door, or even borrow your computer, they are going to leave their germs behind for you to pick up the next day, unknowingly.

According to doctors from Johns Hopkins Asthma and Allergy Center and the University of Virginia School of Medicine, the anatomy of a sneeze happens in the following way:

  1. A sneeze begins when the upper nasal mucosal lining is irritated.
  2. Tiny nerve endings in the nasal lining signal the medulla in the lower brain, commonly known as the "sneeze center."
  3. The brain signals muscles in the chest and throat to contract.
  4. The brain signals the eyes to shut and the palate to close.
  5. Powered by contractions in the chest and throat, the sneeze exits through the mouth clearing the nasal cavity. A combination of saliva and mucus spews from a puddle of liquid between the lips and lower gum and mucus shoots out through the nostrils as well. 

This doesn't bode well for New York subway riders, especially in the winter at the height of cold season or in the spring during high allergy time.

If reading about the anatomy of a sneeze is making you sneeze-phobic, don't worry. There are strategies you can use to help you stay healthy.

Strategies to Stay Healthy During Cold and Flu Season

Wash your hands often. Use soap and warm water and scrub for at least 15 seconds. It's especially important to wash your hands before handling food.

Carry hand sanitizer. When traveling or when there is no access to water, use an alcohol-based (60 to 95 percent) hand sanitizer to help prevent the spread of infection. These gels kill most germs.

Avoid touching or rubbing your nose, mouth or eyelids. If you have to touch any of these, make sure to thoroughly wash your hands first.

Keep your work area and home clean. Use disinfecting wipes or cleanser to clean common surfaces such as door handles, phones, computer keyboards, and countertops.

Keep your distance. Stay three to six feet away from someone who is sneezing, and avoid shaking hands, hugging, or kissing them.

Note: To avoid spreading germs to others, sneeze into a tissue and then throw it away immediately. If there is not a tissue available, sneeze into your upper sleeve. Wash your hands right away.

Sources

Gorgeson, P. Why do we sneeze? Scientific American. April 17, 2000. http://www.scientificamerican.com/article.cfm?id=why-do-we-sneeze. Accessed Dec. 30, 2009.

Kaye, R. The Anatomy of a Sneeze. CNN.com. April 30, 2009. http://www.cnn.com/video/#/video/bestoftv/2009/04/30/kaye.anatomy.of.a.sneeze.cnn. Accessed Dec. 30, 2009.

Mayo Clinic Staff. Influenza (flu), Information Page. MayoClinic.com. http://www.mayoclinic.com/health/disaster-planning/FU00011. Accessed Dec. 30, 2009.

Medical Mystery: Why Do We Sneeze? Sound Medicine, Indiana University. http://soundmedicine.iu.edu/segment/288/Why-do-we-Sneeze-. Accessed Dec. 30, 2009.

Squires, S. & Maloney, B. The Anatomy of a Sneeze. WashingtonPost.com.  http://www.washingtonpost.com/wp-srv/health/interactives/cold. Accessed Dec. 30, 2009.