New Study Finds A 'Cool' New Cause For The Common Winter Cold

Colds and the flu are more common in colder weather, and experts have often thought that the reason why could be that we tend to spend more time indoors around others who may be sick. Other theories include a lack of exposure to sunshine — and, therefore, vitamin D — which helps strengthen our immune systems, per the BBC.

Viruses that cause colds spread easily through the air, making our noses common gateways. We catch colds when we breathe in cold viruses floating in the air after someone sneezes or coughs. Cold viruses can also make it to our noses if we touch them after touching a surface that has cold germs on it, according to the Centers for Disease Control and Prevention. Now, new research sheds light on another reason why we might get more colds in the winter, and it involves the temperature of the air we breathe.

The study, published in the Journal of Allergy and Clinical Immunology, suggests that warm air can help our noses fend off unwanted viruses better than cold air. It turns out that our noses release what is called "extracellular vesicles," or EVs, which are small sacs that block bacteria when they enter the nose, according to U.S. News & World Report.

Researchers of the study exposed participants to different viruses and found that EVs act like "decoys," meaning that viruses attach to them instead of nasal cells. "The more decoys, the more the EVs can mop up the viruses in the mucus before the viruses have a chance to bind to the nasal cells, which suppresses the infection," Di Huang, Harvard Medical School research fellow in otolaryngology at Massachusetts Eye and Ear, tells Harvard Medical School. They then performed tests in colder temperatures and found that the amount of EVs released dropped by 42%. Thus, the findings help explain why cold weather can can be a factor in whether or not we develop an actual cold.