Your mother was right: data suggest that being cold can give you a cold
I have a chilling confession to make: I am that person. The person who always cranks up the thermostat, no matter the weather. Unfortunately, my roommate does not share my penchant for warmth, which means that you will often find me wearing a thick wool sweater, fuzzy slippers, and a Russian ushanka fur hat with my hands wrapped around a steaming mug of tea while I sit shivering on my roommate’s bed, dreaming of Jalapeno peppers and the Kalahari Desert. Exasperated, I’ll shout at my roommate: “Humans are not polar bears! We’re not designed for winter weather — put us in the cold and we end up with a fever and a runny nose.” At this point, my warm-blooded, know-it-all roommate normally replies: “Actually, Sara, despite what you think, cold temperatures are not the cause of the common cold. People hunker down in the winter, and it’s this close proximity — including your sitting on my bed — that allows germs to spread so quickly.”
Pass the Purell
Until very recently, science unanimously supported my roommate’s point of view: colds are primarily caused by the spread of germs among groups of people. The argument makes good sense. When snow starts falling, most of us retreat to warm shelters, be it a tightly packed classroom, a cozy public building, or a crowded coffee shop. And apart from central heating, what do we find in these shelters? Red nosed, tired-eyed people holding fistfuls of tissue, where sneezing, sniffling, and coughing echo from every angle, and where everyone has a desperate desire to take a bath in hand sanitizer.
The idea that germs spread fast in densely populated areas is not controversial or new. But the question remains, why does the common cold pop up so much more frequently in winter? Overbearing parents around the world cannot all be wrong in forcing huge puffy coats, awkward mittens, and ridiculous pom pom toques onto their children. So where does the belief that cold causes colds come from?
Johnny, put on your mitts and toque
People have been using the word “cold” to refer to having a cold since the 16th century, when it was noticed that the illness produced similar symptoms as those caused by exposure to cold weather — a runny nose. But the association between having a cold and cold weather likely existed much earlier. Many people throughout history have been recorded as dying after “catching a chill”, including Russian ballerina Anna Pavlova, writer Emily Bronte, and Sir Francis Bacon. But modern research has often challenged some of these long-held beliefs.
During the 2005 flu season, Dr. Ron Eccles, director of Cardiff University’s Common Cold Centre, led an experiment in which 90 people submerged their feet in ice water for 20 minutes, while a control group of 90 people kept their feet in an empty bowl. Over the following 5 days, 29% of the chilled-feet group developed cold symptoms, compared to only 9% from the control group. At first glance, one might think that this supports the idea that being cold can induce a cold. But Dr. Eccles explained these results by saying that when we are cold our bodies restrict blood flow to our extremities in order to conserve body heat for the brain and torso. Reducing blood flow reduces the body’s supply and access to white blood cells, which are the immune system’s primary weapon against germs. In other words, Dr. Eccles argued that cold temperatures were not directly responsible for causing the colds — but they still played a central role.
Similarly, Norwegian health folklore has long held that women are more likely to develop urinary tract infections when the weather is cold. When Norwegian researchers conducted a similar experiment to that of Dr. Eccles, they found that submerging feet in cold water did seem to activate UTIs in some women, lending further support to the idea that low temperatures cause illness. But definitive proof was still missing … that is, until now.
The cold hard truth
In late 2014, a team of researchers from Yale University discovered that low temperatures led to a reduced immune response in the nose and throat cells of mice. Simply put, they discovered that cold temperatures make mammals more susceptible to and strengthen the affect of infections caused by the rhinovirus, which is one of the main viruses that cause the common cold. Of course, staying away from people already infected with the rhinovirus will still lessen your chances of catching it, but the study implies that the less time you spend in winter weather, breathing in cold, frosty air, the less likely you are to get a cold. Although scientifically novel, these findings won’t come as a surprise to most people, including parents the world over.
But why did it take until 2014 for science to catch up with common knowledge about the common cold? Maybe it is because science is famous for all of those times when it has proved us wrong. That the earth rotates around the sun was such an exciting discovery mainly because everyone thought it was the other way around. For hundreds of years, people believed that washing their hands was not important and resisted science telling them otherwise, with devastating consequences. So frequently has science tried to convince people that their views are misconstrued or incorrect that perhaps now it is on the defensive?
With this new article, perhaps intuition and science will start to realize they are not always adversaries. Maybe the future will be filled with scientists that accept that — as in the case of the Yale scientists — sometimes the answer is right in front of your nose.
This article was written by Sara-Elizabeth Tsimerman, a fourth-year undergraduate science student at Western University. This essay is the product of a science-writing internship in David Smith’s Lab at Western.
