Cold weather brings with it the risk of catching a cold. No doubt, you hear more people sneezing, sniffling, and coughing when the temperatures drop. Even worse, flu makes its rounds as the temperatures drop as well, leading to a loss of productivity and income.
Who has time for colds and flu? The reality is that the average adult gets between two and four colds per year, more often in the fall and winter, whereas kids, due to their less mature immune system, get between five and ten.
Have you ever wondered why colds are more common in cold weather? You may have heard that colds spread more easily in the winter because people spend more time indoors and that’s one reason colds inflict more people when the temperatures drop. But does the cold weather itself, shivering outdoors on a cold, winter day, also increase the risk of catching a cold?
Those Pesky Cold Viruses
Cold viruses are of several different types. In fact, over 200 viruses have been linked with the common cold. The most common is a group of viruses called rhinoviruses. These sneaky viruses are naturally drawn to the mucous membranes of your nose and throat where they proliferate and set up an infection. Rhinoviruses are responsible for about half of all colds. Other cold-causing viruses are coronaviruses and parainfluenza viruses.
Surprisingly, up to 30% of all colds may be caused by viruses we haven’t identified yet. Needless to say, all of these viruses are inconvenient to have. Fortunately, few people die from the common cold. Despite their relatively benign course, we’d like to avoid getting one if at all possible. Can staying warm help you prevent one?
Does Exposure to Cold Air Increase the Risk of Catching a Cold?
As mentioned, colds are caused by viruses, and rhinoviruses are the most common cause of a cold. Studies looking at replication of rhinoviruses in mice shows this virus that causes the sniffles and sneezes replicates fastest at a temperature of around 91.4 degrees F, well below the average body temperature of 98.6 degrees F. So, if you step out into a cold environment, your body temperature drops and it creates conditions that are favorable for rhinoviruses to gain a foothold in the mucous membranes of your nasal passages and throat.
Of course, your immune system helps protect you against the rhinovirus but studies show that the immune system doesn’t fight off these viruses as effectively when your body temperature drops. Your immune system functions best in a warm, toasty environment and when you get chilled, your immune system loses some of its ability to fight viruses. Another study published in the journal Viruses found that low temperature AND low humidity in the air boost the ability of rhinoviruses to proliferate and cause a cold. So, it’s not an old wives’ tale that getting cold increases the risk of catching a cold.
What Can You Do to Prevent a Cold?
Naturally, you’d like to know how to prevent the common cold. There’s not a surefire way to do that but, based on the research, reducing exposure to cold and changes in temperature from warm to cold may help. So, take action! When you go outside on a cold day, wrap a scarf around your lower face to reduce heat loss through your mucous membranes. Since low humidity is a factor too, add a humidifier to your home, especially your sleeping area if you live in a dry environment. Humidity levels drop in the winter and you’re fighting both cold and low humidity.
In one study, looking at influenza viruses, another type of respiratory virus that makes its mark in the fall and winter, researchers found that raising the humidity level to 43% or higher deactivated 86% of airborne virus particles. When the air is saturated with water, it reduces the transmission of cold viruses. So, don’t let your home or office become too dry.
Are there other ways to ward off colds this winter? Since you need a healthy immune system to fight off cold viruses, make sure you’re eating a healthy, balanced diet with lots of fruits and vegetables. Fruits and vegetables contain phytochemicals that help balance your immune system as well as vitamin C, a powerful antioxidant vitamin. Although there’s no strong evidence that vitamin C prevents colds, some studies show it shortens their duration by a day or so. Finally, check your vitamin D level. Vitamin D is important for healthy immune function. One study found that taking a vitamin D supplement was linked with a 12% reduction in the incidence of colds. Remember, in the winter, you get less direct sunlight and it’s harder to keep your vitamin D level up.
Of course, you should also remember the common-sense stuff. Cold viruses spread very easily. In fact, a study carried out by the University of Virginia looked at how long rhinoviruses, a type of cold virus, remain capable of infecting humans. Surprisingly, they found that the virus from infected individuals remained capable of spreading for longer than expected. They were able to isolate active virus from the items the participants touched for up to a day afterward. So, avoid sick people, particularly touching surfaces they’ve touched, and wash your hands often.
The Bottom Line
Colds are a nuisance and it’s better to avoid them than to treat one after its gained a foothold. Yes, getting cold may increase your risk of catching a cold and humidity is a factor as well. Bundle up when you go outside and cover your nose when possible. Make sure the indoor areas where you spend time have a humidity of 43% or higher.
WebMD. “What’s Causing My Cold?”
Viruses. 2016 Sep; 8(9): 244. Published online 2016 Sep 2. doi: 10.3390/v8090244.
WebMD. “Vitamin D Tied to Lower Risk of Colds, Infections”
Centers for Disease Control and Prevention. “Common Colds: Protect Yourself and Others”
WebMD. “Higher Indoor Humidity Levels Might Slow Flu”
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