Does Cold Weather Cause Colds?

Much like the common cold, some myths will never die. That's the topic of this week's Healthcare Trio. Cold weather does not cause colds. I've written about this on my blog, in my books, and I've talked about it in news interviews, but no amount of effort seems to put this myth to rest. But here we go again with another study published and more people telling me I was all wrong. Sorry, but I've looked at the study and I'm sticking to my guns. This latest research, published in the Journal of Allergy and Clinical Immunology, is touted in the news circuit with headlines like, Scientists finally know why people get more colds and flu in winter. No, we don't. We have some guesses, like perhaps people spending more time cooped up inside with other people makes it easier for viruses to spread. But we pretty much know that cold weather isn't the culprit. But before we get to how we know that it isn't, let's first talk about this study. If you read the news articles, you might think that researchers reduce the temperature inside a human nose and then measured how many viruses and bacteria fighting cells were killed in the nostril. What they in fact did was take nasal mucosal samples from humans, did some cell cultures in a dish, and reported that antiviral activity was significantly impaired at 32, but not 37 degrees Celsius. Everything they did was a bit more complicated than that, and they were investigating a specific mechanism of this change in antiviral activity, but you get the gist. But come on, 32 degrees Celsius is 89.6 degrees Fahrenheit. That is not cold. Sure, it's colder than the control, which was 98.6 degrees Fahrenheit, but I don't think anyone is worried about getting a cold at 89.6 degrees Fahrenheit. Also, and I know we've said this before, but it bears repeating a million times, what happens in cells inside of a dish can only tell us so much about what happens inside of the human body, where a bunch of other cells exist and interact in an environment that probably looks like chaos compared to the very controlled environment of a petri dish. But so what, you may say. This gives us a hint that lowering temperature affects our ability to fight off colds. Now we can move forward to randomized controlled trials and confirm our suspicions. Yeah, but sorry, someone already beat us to that. As far back as 1958, in that year, a randomized controlled trial was conducted to see if people were more likely to get sick when cold after being exposed to a cold virus. To do this, they put one group in a room where they sat in their underwear at 80 degrees Fahrenheit, and a second group who sat in their underwear in a room that was 60 degrees Fahrenheit, and a third group who wore clothes, overcoats, gloves, and hats in a room that was 10 degrees Fahrenheit. Everyone was exposed to a cold virus, but no one ended up with a higher chance of getting sick, even those in the coldest room. Another study I've covered before from 1968 exposed people to a cold virus and then subjected them to cold or warm temps at various intervals from inoculation all the way to recovery. No differences were found in infection, reaction, or recovery rates between groups. As I've written before, there are certainly published papers that disagree with me here, but when I look at these papers, they are usually unconvincing for reasons such as not actually using cold temperatures or using temperatures so cold we'd be getting into the realm of hypothermia, which is a different matter than simple cold exposure, or they're looking at cellular responses in a dish, and I just don't buy it. We do seem to get sick more in the winter, but it's more likely to be because of the way we behave when it's cold outside. We stay cooped up together inside a bunch more than we do in the summer, which means it's much easier to pass our colds and other sicknesses to each other. In that sense, you're probably better off heading outside in the winter, appropriately clothed to avoid things like frostbite and hypothermia, of course. Hey, did you enjoy this episode? You might enjoy this previous episode, also on cold weather myths. We'd like it if you'd like the video, subscribe to the channel down below, and consider going to patreon.com slash healthcare triage, where you can help support the show, make it bigger and better. We'd like to especially thank our research associates, Joe Sevitz, Edward Lilleholm, and Brian Nam, and of course, our Surgeon Admiral, Sam.