Why do we sneeze?

“Bless you!” It’s a phrase we may say and hear multiple times in a day. But have you ever stopped and wondered what happens in the human body to cause us to sneeze?

Dr. Dina Golbin-Hallett, an otolaryngologist at Advocate Sherman Hospital in Elgin, Ill., explains that sneezing is just a reflex.

“It starts with an irritant reaching the inside of our nose, such as chemicals, dust, animal dander, germs or pollen,” she says. “Because our body senses that the irritant is not supposed to be there, this stimulates the nerve endings in our nose, which then sends a message to our brain to get rid of the irritants.”

While sneezing is meant to clear irritants from your body, one sneeze can expel germs at 100 miles per hour and can release hundreds of thousands of germs into the air around you.

“The brain sends a signal to our lungs to take a big deep breath against tightened chest muscles causing pressure to build up,” Dr. Golbin-Hallett says. “Then the tongue presses against the roof of our mouth and with a big “ah-choo” the pressure is released through the nose, which expels the irritants.”

Dr. Golbin-Hallett says to prevent getting others sick or simply from grossing other people out, make sure to cover your sneeze with your arm or a tissue.

“Cover your nose and mouth with a napkin, tissue, your sleeve or anything to keep the expanding cloud of germs from escaping into the world,” she says. “Also make sure you clean your hands thoroughly, and often, to prevent the spread of germs.”

Holding in your sneezes is also harmful to your health. Dr. Golbin-Hallett explains that holding in a sneeze can build pressure in your head and ears, causing the ear drums to rupture, damaging the sinuses or potentially even bursting blood vessels in the head.

If you are having trouble sneezing, try looking up at a bright light to induce the sneeze, Dr. Golbin-Hallett says.

“Sneezing from a bright light is a genetic tendency known as ‘photic sneezing’ or ‘sun sneezing,'” she says. “It is caused by a connection between your nose, eyes and brain called the nasal ocular reflex that can cause sneezing when looking at bright lights. Sun sneezing affects 18-35 percent of the population. Although the exact mechanism is not scientifically clear, it is known to run in families.”

Although sneezing is completely natural and healthy for your body, sneezing too much could indicate an allergy. Dr. Golbin-Hallett says if symptoms persist, to see an ear, nose and throat doctor and request an allergy test.