The Real Reason Cold Weather Makes It Easier To Catch A Cold

When we're just children, we're taught to layer up against the cold when going outside in the fall and winter months. In addition to comfort, the idea is that we're better protected against colds and viruses by keeping warm.

Research backs up that idea with proof that the viruses that cause colds (rhinovirus is the most common) can incubate and grow more easily when your nasal passages are cool than when they are warm. It's a study that was published in the journal Proceedings of the National Academy of Sciences, using mouse cells to test the theory.

In the study, scientists found that cold viruses replicated more easily when nasal passages were cool — about 33 to 35 degrees Celsius — than when they were at the core body temperature of 37 degrees Celsius. Previous research backed up this idea, so this time they went a step farther and also tested the body's immune system response, according to The Healthy.

Akiko Iwasaki, study author and professor of immunology at Yale University explained, "We found that the innate immune response to the rhinovirus is impaired at the lower body temperature compared to the core body temperature."

Other factors to consider about colds and cold weather

While this study focused on new information, there are some timeless truths that should be kept in mind for winter health. More people congregate indoors during cold weather, putting them in close proximity. That allows for easier transmission of a variety of viruses and bacteria, according to Winchester Hospital. They also note cold temperatures put stress on the body, which animal studies have shown makes it harder for the immune system to fight infection.

It's also thought that cold and virus molecules thrive in the low-humidity environment of winter, including the drier lining of the nose. Dry air narrows blood vessels in the nose and upper respiratory system, which doesn't allow infection-fighting white blood cells to reach the area, according to Medical News Today.

We aren't at the mercy of the rhinovirus during the winter months, however — there are things we can do to protect our body from viruses. Bundling up against the cold is important, and you'll want to wash hands consistently and consider using a humidifier or nasal spray to irrigate the nasal passages and keep them ready to fight off viruses.

Here's to comfort and health all winter long.