Winter is coming early to much of the United States this year, with freezing temps arriving this week.
Researchers say a quick drop to cold temperatures may make you more likely to get sick.
But it’s not just because the weather is cooler. Viruses can live longer in colder temps.
A strong arctic cold front is sweeping across the United States this week, with some areas in the Midwest already experiencing record-breaking temperatures for this time of year.
As the temperatures hover in the single digits, it’s natural to suspect the risk of contracting the common cold or flu is more pertinent than ever.
Winter is, after all, the peak season for sore throats, coughs, and runny noses. And a sudden drop in temperature, like the ones we’re seeing in this cold front, makes it even more likely that we’ll get sick.
When temperatures quickly plummet and take humidity levels down with it, viruses tend to get stronger, and our immune system can take a hit.
According to health experts, however, it’s not cold weather itself that makes us sick — but lower temperatures do increase our risk for infections in a few ways.
“Data indicates that viruses survive and proliferate more effectively at colder temperatures, allowing them to spread and infect greater numbers of people in colder temperatures,” said Dr. Robert Glatter, an emergency physician with Lenox Hill Hospital in New York City.
“Coupled with this, colder weather can blunt the immune response, increasing the chance that you may get sick,” he said.
Viruses like cold, dry air
We have hard evidence that rhinoviruses — the cause of most colds — do best in dry, cold air.
One study looked at how viruses acted in various temperatures and humidity levels. Researchers found that colder temperatures and drier air increased people’s risk for rhinovirus infections.
When a virus first comes in contact with the body — specifically, the nose or throat — it multiplies to cause an infection. When our body temperature drops, as it does in cold weather, viruses have an easier time multiplying.
In addition, colder temperatures provide the flu virus with a protective layer, making it firmer and less penetrable, Glatter explains.
In warm, moist weather, the virus loses that hard layer and becomes softer, thus less likely to spread from person to person.
Our immune system suffers
At the same time, drier air impairs our immune system’s ability to fight viruses, according to Dr. David Cutler, a family medicine physician at Providence St. John’s Health Center.
“In addition, the drier air impairs your body’s local immune reaction to the arrival of the virus. Some have theorized that extreme cold will cause constriction of blood vessels, which further impairs the local immune response,” Cutler said.
The cold essentially makes it harder for white blood cells to reach the mucous membrane — where cold virus camp out and create an infection — and start attacking the virus.
The short, dark days of winter don’t help, either. Due to the lack of sunshine and time spent indoors, people tend to have lower levels of vitamin D, a vitamin that typically helps keep our immune system up and running.
We tend to stay indoors
The viruses that spread the common cold circulate through air and close personal contact. It’s understandable, then, that transmission picks up when we huddle indoors together during frigid weather.
“In the winter, and especially when it is cold, people congregate indoors more and spread viruses more,” Cutler said.
Both common colds and the flu are very contagious. A cough can expel germs up to 6 feetTrusted Source. Most germs can survive on surfaces for a while.
“Rhinoviruses and other cold viruses can survive up to 7 days on indoor surfaces, countertops, or doorknobs. Flu viruses generally can only survive for about 24 hours. All viruses thrive better on hard surfaces — metal or plastic — than soft fabrics,” Glatter said.