Does Being Cold Make You Get a Cold?

Sam Westreich, PhD

Shiver in the cold, get sick? Science says no… but sometimes yes?

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Is this bundled-up woman at a lower chance of getting a cold?Photo by freestocks on Unsplash

Growing up in the Midwest, winter brought an assortment of ailments: scratchy noses, dry throats, water and dirt getting everywhere in the house from melting bits of snow, and common sneezes. It felt like I caught a cold almost every year.

It made sense — it’s in the name. You get a cold because you’re cold, and a few weeks of sneezes was a small price to pay for the energy savings of keeping the house perpetually at 66 degrees Fahrenheit. Put on a sweater!

Now, living on the west coast in sunny California, the temperature almost never drops to the point where water becomes solid, and I get fewer colds. Again, seems to make sense…

…but are the two really linked? How does that make sense from a biology perspective? How could being cold cause me to catch a cold?

Let’s look at what the science says about the link between temperature and infection.

Both cold, and colds, can be deadly

First, when we talk about the “common cold”, we’re usually referring to a viral infection that attacks our upper respiratory tract (our nose and throat). There are a number of different types of viruses that can infect us:

  • Rhinoviruses (most common culprit, responsible for about half of all colds)
  • Coronaviruses
  • Influenza viruses
  • Other viral types (parainfluenza virus, respiratory syncytial virus, adenovirus, and enterovirus)
  • Bacteria, either Chlamydia (different type from the genital infection), Haemophilus, or Streptococcus

Out of 138 examined patients in the study linked above, only 7 showed signs that their cold was due to bacteria; it’s primarily a viral disease.

For most healthy people, a cold is just a collection of irritating but not-too-threatening symptoms, like a runny or stuffy nose, a mild fever, sore throat, coughs, mild body aches, sneezing, and congestion. But for infants, young children, people with weakened immune systems, or people with other chronic health conditions, colds can be potentially dangerous.

Colds can also cause ear infections if the virus travels from the upper respiratory tract to the ear. It can also lead to other infections, like strep throat, pneumonia, which are more dangerous and should be treated by a doctor.

Takeaway: Most colds are viral infections. How could these come about from being cold?

Chilliness is an indirect cause, not THE cause

Being cold, on its own, does not give you a cold. Viruses do not spontaneously materialize. If you were placed in a sterile enclosure with no viruses and the temperature was kept at a keep-you-shivering 50-something degrees or colder, you would not spontaneously get sick.

But winter does make us change our behaviors, and it alters the environment. It’s these changes that make us more susceptible to viral infections.

Dryness. In winter, the air is drier; water freezes and condenses out of the air outside, and the heating systems that warm our house also dry the air indoors.

  • In drier air, tiny water particles from sneezes or coughing stay in the air longer, making it easier for viruses to spread.
  • Dry air dries out the mucus in our nose, which means less of a barrier blocking viruses from gaining access to their target.

Clustering. When it’s cold, we tend to spend more time doing indoor activities, which puts us in closer proximity to other humans. This offers more opportunities for the virus to spread from one person to another.

Do we get weaker from being cold?

A common suggestion is that the chilliness of winter may weaken our immune system, making us more susceptible to infections in general. Studies suggest that this may be the case, thanks to our cells’ different levels of antiviral defense activity at different temperatures.

At colder temperatures (33 degrees Celsius {91 degrees Fahrenheit} versus the normal 37 degrees {98.6 degrees Fahrenheit}), mouse airway cells showed significantly lower levels of expression of antiviral defense genes. Colder temperatures meant that the cells that are getting infected are less able to mount a defense.

Similarly, the rhinovirus most commonly responsible for colds is also better able to replicate at lower temperatures. This means that, when we’re cold, we produce fewer antiviral defenses, while the virus can replicate more rapidly.

Of course, this is an acute effect, rather than a chronic one. When we warm back up, our cells resume their normal activity levels, and being cold has not been shown to create long-lasting, persistently weakened immune systems.

Interestingly, being cold in other areas besides the airway may still make you more likely to get sick! One study chilled the feet of college students by placing their feet in icy water for 20 minutes. 13/90 of the cold-footed college students came down with colds in the next week, versus only 5/90 warm-footed control subjects. Students who came down with colds also reported that this was a frequent occurrence for them, suggesting there may be a sub-population of people who are especially susceptible to viral infections and it only takes a small weakening of the immune system to get them sick.

In conclusion: being cold doesn’t directly cause colds, but it contributes

At the most basic level, being cold does not make you spontaneously get sick. You need to be exposed to a virus as well.

But a cold environment makes us more susceptible to viral infection :

  • Dry air lets viruses stay in the air longer.
  • Dry noses have less protective mucus.
  • Cold weather keeps us indoors, closer to each other, increasing disease spread.
  • Colder air may reduce the viral defense capabilities of the cells lining our airway.
  • Viruses replicate faster at colder temperatures.
  • Winter means less sun exposure, which means less vitamin D (a vitamin that bolsters our immune system).

For most of us, colds are an annoyance, not an existential threat — but we still would rather avoid them if possible. The best way to do so is to try to prevent being infected in the first place. Limit exposure to crowds or to infected individuals.

And hey, we’ve all gotten good at wearing masks. Masks aren’t just for Covid; they can also help prevent the spread of other disease, like colds, as well! They’re more acceptable to wear now, so maybe consider putting on a paper mask when you visit the mall this winter.

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A microbiome scientist working at a tech startup in Silicon Valley, Sam Westreich provides insights into science and technology, exploring the strangest areas of biology, science, and biotechnology.

Mountain View, CA
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