Usually a virus or bacteria enters the body through the nose. Then the tip of the nose recognizes the germs immediately, long before they are recognized by the nose itself—that is, by the main part of the olfactory organ—according to one of the findings of the research.
At this point, the immune cells permanently present in the nose begin to make billions of copies of themselves. These are called extracellular vesicles, or EV for short. Dr. explains. Benjamin Bleier, MD, director of the Department of Otolaryngology at the Massachusetts Eye and Ear Institute. “EVs act as decoys, so if you breathe in a virus, that virus sticks to those decoys instead of entering the body.”
The study found that when attacked, the nose increases the production of EVs by about 160 percent, and is therefore – below average temperatures – well-armed for common viruses and bacteria. However, when temperatures drop just above freezing, things look different.
To simulate this, the research team exposed four study participants to temperatures of about four and a half degrees Celsius for 15 minutes and observed their nasal cavities. “We found that the temperature around the nose can drop by up to five degrees Celsius when exposed to cold air.” That’s enough to turn off the immune benefits of the tip of the nose, Bleier explains. 42 percent of the EV is lost in this cold.