Can You Get Sick From Running in the Cold?

There's no question that exercise is good for your physical, mental and emotional health — no matter where you choose to get active.

But when the pandemic led gyms across the nation to shut their doors, more Americans than ever began working out in the fresh air, according to an August 2020 report from the Outdoor Industry Association.

In many ways, that was a positive shift. Research confirms that al fresco fitness can be even more beneficial than visiting a gym or working up a sweat at home. For instance, a January 2019 study in the ​Journal of Sport and Health Science​ suggests that people who get moving outside experience greater feelings of enjoyment and satisfaction, and are more likely to stick with exercise compared with those who stay in.

But now, as temperatures plummet in many areas of the country, heading outside presents new challenges. In fact, nearly half of people actively put off outdoor exercising in the winter, according to the ​Journal of Sport and Health Science​ study.

If you give running outside the cold shoulder once the weather turns, you probably have one big question in mind: Can you get sick from running in the cold?

Since it's more important than ever to stay healthy these days — and because fitness is so critical to our wellbeing — we (virtually) sat down with infectious disease specialists to find out if can get sick from running in the cold.

Can you get sick from running in the cold? To answer that question, you first need to rewind a bit.

After all, growing up, your parents may have told you that you need to button up in the winter so you won't catch a cold, but science says otherwise. "This old-fashioned concept has been thoroughly studied and disproven," says MarkAlain Déry, MD, medical director of infectious disease for Access Health Louisiana.

Evidence that no, the cold won't give you a cold, goes all of the way back to October 1968 when, in a landmark ​New England Journal of Medicine​ study, 44 volunteers were put in either a 39 degrees Fahrenheit room or submerged in a 90 F water bath. Then they were inoculated with the rhinovirus. Researchers closely tracked the subjects; compared with controls, they found no difference in infectivity, duration or severity of illness, immune response or recovery depending on the temps they had hung out in.

Simply put, the cold isn't a virus or bacterium. So the cold alone can't infect you, says Jennifer Veltman, MD, chief of infectious diseases at Loma Linda University Health.

The cold, flu and COVID-19 are all viral infections. According to the Centers for Disease Control and Prevention (CDC), colds spread through the air or via close contact with someone who's infected. You might also catch a cold if you handle a surface that has viral particles on it, such as a doorknob, and then touch your mouth, nose or eyes.

The flu and the novel coronavirus spread in a similar same way, per the CDC, although the primary means of transmission is through droplets when someone coughs, sneezes or talks, rather than by touching surfaces. Viral flu particles can project up to six feet and cause infection if they either land directly on your mouth or nose or are inhaled. According to the CDC, mounting evidence shows that aerosols containing the novel coronavirus can travel even farther than six feet and can remain suspended in the air for extended periods of time.

Meanwhile, a respiratory virus, such as a cold or flu can lead to acute bronchitis. According to Johns Hopkins Medicine, this occurs when the lining of your breathing tubes become inflamed, causing increased mucus and coughing.

The National Institute of Health explains that bacterial infections can spread via respiratory droplets, close contact with sick people or animals, ingesting contaminated food or water or touching a bacteria-infested surface and then touching your mouth, nose or eyes.

So if cold weather itself can't give you an infection, why does cold and flu season align with the chillier months of the year? "People are more likely to huddle indoors," Dr. Dery says. "Any time you are in a room sharing airspace with others, you are exposed to whatever pathogens they are carrying."

In addition, the air tends to be drier in the winter, facilitating viral transmission. An animal study published in the April 2014 issue of the ​Journal of Virology​ revealed that influenza spreads more easily in dry environments. A September 2016 study in ​Viruses​ found similar results for the cold virus, and a November 2020 study in ​Transboundary and Emerging Disease​ confirmed that a 1 percent decrease in humidity is linked to a 7 to 8 percent increase in COVID-19 cases.

Bacteria, meanwhile, vary greatly in their response to relative humidity, according to a December 2009 study in the ​Journal of the Royal Society Interface​.

If you come down with the sniffles or achy muscles during a run, it doesn't necessarily mean you're sick.

It's common to get a runny nose when you're exercising in frigid temps. When you breathe in dry, frosty air, the body responds by producing extra mucus, Dr. Dery says. That extra mucus actually helps keep you healthy. A March 2017 study in ​PLOS ONE​ confirms that mucus helps clear pathogens out of your system and, when the respiratory tract becomes excessively dry, the risk of upper and lower respiratory infections increases.

Some people also experience a sore throat after a jog in icy weather. "The excess mucus can trickle down the back of your throat, creating irritation," he says. "But it's not harmful, and it will stop when you go inside."

"If you have reactive airway disease, asthma, chronic obstructive pulmonary disease or emphysema, running in the cold causes the muscles in your airways to constrict," Dr. Veltman says. "This can make it difficult to breathe and exacerbate your condition." Even in those without asthma, running in the cold can trigger this exercise-induced bronchoconstriction, often experienced as wheezing, chest tightness and coughing.

A shivery workout might cause sore or achy muscles, too. "The cold affects your circulation, which can make your joints feel stiff," Dr. Dery says.

"No matter the weather, you are actually ​less​ likely to contract a respiratory illness when you are outdoors," Dr. Dery says. "Because these viruses are largely airborne, the particles dissipate in the open air and become diluted, compared to stagnant indoor air."

To that end, running outside is much safer than hopping on the treadmill at a gym, where you're exposed to public surfaces and air that others are inhaling and exhaling.

And if you find yourself struggling with a runny nose, sore throat or muscle aches, you can take some comfort in the fact that you likely aren't ill. Keep "symptoms" at bay by doing a quick indoor warm-up before you head out the door, wearing multiple easily-removable layers, and talking to your doctor about a steroid nasal spray or inhaler to reduce swelling and relieve drippy, stuffed-up nostrils.

To keep your risk of infection at its lowest when running outside in the cold, practice the same safe strategies you do outside of your workouts.

"When you're running outside on your own during the COVID-19 pandemic, you can pull your mask down — but leave it under your chin so that it's easy to lift up if you encounter someone else," Dr. Dery says.

Be sure to bring your own water bottle rather than drinking from a water fountain, and wash your hands or apply disinfectant if you touch a public surface — say, if you take a break on a park bench or use a restroom while you're out.

"If you're with a buddy, it is necessary to wear a mask the entire time and stay in different 'lanes,' staggering yourselves instead of jogging directly behind the other person," he says.

The bottom line: If you're worried that jogging in the cold might make you sick, you can probably chill out. With a few exceptions, outdoor exercise is almost always cool.