Do cold temperatures cause colds?

The day after the temperature dipped from 60 degrees to 25 degrees, I mistakenly left for work without a winter jacket. Rushing 50 yards to the hospital doors with my arms clung to my chest in the blistering cold, my tie flew over my shoulders, my teeth chattered, and my fingers went numb.

That evening I began to sniffle. The next morning I had a sore throat, and the following day my nose would not stop running during a meeting. So I wondered, does being out in the cold cause you to get the cold?

As an infectious disease doctor, I felt a little embarrassed that I didn’t know the definitive answer to this simple question. Especially since I repeatedly rebuke my teenage children for not taking a jacket to school or wearing socks and a sweater at home.

I learned in medical school that the common cold, a viral infection, is not caused by its namesake “the cold” but rather by a small infectious agent that infiltrates the cells and hijacks the cell’s machinery to replicate itself until the culprit particles are effectively destroyed by the immune cells of the body.

So I began my search to find the reason for the correlation. (Yes, doctors do Google searches to find medical answers too — cautiously though). The most entertaining and informative resource was the asapscience video, which had 4.3 million views.

Here are some facts. Without doubt, during the winter time there are an increased number of respiratory infections caused by over 200 difference viruses, including picornaviruses (common cold) and orthomyxoviruses (influenza). In the winter, as many as 5 of 100 patients coming to the emergency room have a “flu-like illness” compared to less than 1 per 100 during the summer seasons.

So what is it about the winter season? No one knows for sure, but there are three possible reasons. First, during cold winter days people tend to stay indoors leading to more person-to-person interactions and increasing the spread of hundreds of viruses.

Second, cold weather leads to lower humidity, which causes the mucous in our nostrils to become dry, hence reducing the protective layer. One study on guinea pigs showed that a respiratory virus is transmitted much more easily at 20 percent humidity and 41 degrees compared to not at all at 80 percent humidity and 86 degrees.

Lastly, in the winter season people get less vitamin D due to lower sun exposure, leading to lower immune response, which may cause increase infections by the cold viruses.

Honestly, I didn’t find any of these arguments very convincing, so I researched further and found an interesting study about getting a cold after having cold feet. In a 2005 study in Family Practice Journal, researchers studied 180 subjects and randomly dipped half the subjects feet in a 10 degree bowl of water for 20 minutes. A few days later, 13 of the 90 chilled subjects reported cold symptoms compared to 4 of the 90 un-chilled ones. For me, this study put it all together.

So here is what I think happened to me. The day the temperature dipped below freezing and I was walking in and out of hospitals without my jacket, the cold temperatures caused my blood vessels to vasocontrict — that is, to take blood away from the surface of my skin to the core of the body in order to conserve heat. (Studies from the cold feet study show that even when feet are placed in the cold, the vessels of the nose vasoconstrict.) This led to less blood flow and less protective white cells to the face and nose area and less mucous and further virus replication.

Also, it was likely that I had dormant “subclinical ” viruses in my nose, which were acquired due to increased person-to-person interaction during the winter season, and one of these viruses found the perfect opportunity, with my depressed immune system, to attack. End result: a cold due to the cold.

So my suggestion of best ways to prevent the cold is to follow the Super Bowl teams’ strategy — a good defense. We can build our immune system by eating right (getting our vitamins A, C, D and E through fruits and vegetables), getting sleep over 7 hours a night, doing relaxation and meditation for 10 minutes a day, exercising regularly for 30 minutes a day, and staying bundled with a warm jacket and thick socks.

Now only if I can follow my own advice.

Manoj Jain is an infectious disease physician and contributor to the Washington Post and The Commercial Appeal.  He can be reached at his self-titled site, Dr. Manoj Jain. This article originally appeared in The Huffington Post.

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  • Ron Smith

    Hi, Manoj. Good article. Here are some of my own recent thoughts.

    “So here is what I think happened to me. The day the temperature dipped below freezing and I was walking in and out of hospitals without my jacket, the cold temperatures caused my blood vessels to vasocontrict — that is, to take blood away from the surface of my skin to the core of the body in order to conserve heat. (Studies from the cold feet study show that even when feet are placed in the cold, the vessels of the nose vasoconstrict.) This led to less blood flow and less protective white cells to the face and nose area and less mucous and further virus replication.”

    We moved into an old farmhouse recently that we had redone some years ago. I put in some Netatmo monitors which provide temperature and humidity and CO2 levels in four locations in the house.

    The changes in humidity are striking especially as we observed with the recent severe cold fronts, the last of which paralyzed the Atlanta area. Senoia is situated just 20 miles south.

    What I observed is that the heated air has a sudden precipitous fall while the outside colder air shows a rise in humidity. The falls occur at night while we are sleeping of course. We have some open flame heating which contributes to this I’m sure.

    It was after these fluctuations that we developed our first ‘sore throats.’ This caused me to conclude that we probably are breathing more through our mouths with the general nasal congestion brought on from just the change in air temperature in general. This meant clear runny noses in the daytime with dry mucous crusts upon waking. (My grandsons call this a snobby nose!)

    As I have long suspected, many ‘colds’ are actually not viral or bacterial, at least at the beginning of the winter season change. That at least helps explain why I see antihistamines dry these kind of noses up and relieve symptoms, even though they are not ‘allergies.’ They still respond to the decreased mucous production effect, and thus may actually prevent viral spread through droplet transmission.

    Warmest regards,

    Ron Smith, MD
    www (adot) ronsmithmd (adot) com

  • Morgan Feeney

    You seem to be drawing a very definitive conclusion based on one small study! A study which, by the way, you seem to have misquoted – following the hyperlink you provided, I see that it was 5 out of 90 who got a cold in the control sample, not 4. Not a very large difference, but then – there isn’t a very large difference between 4 or 5 and 13, after all, is there? One must question how statistically significant the findings of this study are.

    You extrapolate from the model in the paper (20 minutes of immersing feet in chilled water) to your own immersion in chilled air, while actively moving, for a distance of 50 yards – which presumably took less than 20 minutes. Aside from an argument about vasoconstriction being similar in the two conditions – there are many other differences here!

    There have been other studies showing no causal link between exposure to the cold and development of cold systems, and it is not clear from your article here why you have chosen to ignore these studies and focus only on the data which support your chosen hypothesis.

    While the common cold is not a serious illness, many other diseases are. I hope that you take more care to read the literature, think critically about it, and make more reasoned judgements in those cases. Moreover, even when lives are not potentially at stake, one would hope to find a physician setting a better example.

  • Rob Burnside

    Entertaining and informative–we can’t ask for more! Next, perhaps, your thoughts on “cabin fever.” What is it? Where does the term originate? Is it transmissible? What are the best remedies?