Will exercising with a cold make you sicker?

Is it safe to exercise when you are sick with a cold? And if so, what exercises are best?

A: Whether you’re a die-hard exercise devotee or just beginning to get into a workout groove, you may worry that coming down with a cold could derail your training routine. Does your runny nose mean you need to skip your exercise session, or could a workout actually do you some good?

Researchers have looked into this very question and have concluded that a mild cold does not always have to sideline you. But there are several key caveats to keep in mind. We talked to the experts behind the research to highlight what you need to know.

Do the “neck check”

Before you don your workout gear, assess your symptoms carefully.

“The most popular advice is to do what’s referred to as the neck check, where if symptoms are above the neck, exercise is probably safe,” said Thomas Weidner, a professor of athletic training and chair emeritus of the school of kinesiology at Ball State University in Indiana.

If your only symptoms are nasal congestion and a low-grade headache, for example, a light workout shouldn’t make your cold worse.

In fact, a landmark study that demonstrated this was led by Weidner in the 1990s. In it, 50 young adults were infected with the common cold virus and randomly split into two groups: one that did 40 minutes of moderate exercise every other day for 10 days, and one that didn’t exercise at all.

The researchers found that there was no difference in illness length or severity between the two groups — meaning that working out moderately did not prolong or exacerbate their colds. Other research done by Weidner has led to similar findings.

If you do have symptoms below the neck, such as a hacking cough, chest discomfort, nausea, diarrhea or bodywide symptoms like fever, muscle aches or fatigue, “then it’s not a good idea to exercise,” Jeffrey Woods, a professor of kinesiology at the University of Illinois at Urbana-Champaign, said via email.

Monitor your symptoms

Also keep in mind that symptoms can evolve, and what might begin as a runny nose could later become something more serious, like bronchitis or the flu. Proceed with caution, keep tabs on how you’re feeling and skip the workout if you start to feel worse.

“There’s this myth that you can sweat out a virus, but that is a terrible thing to do,” said David Nieman, a professor of biology at Appalachian State University and director of the Human Performance Laboratory at the North Carolina Research Campus.

If you’re not feeling good, heavy exercise can exacerbate your symptoms and increase your risk for complications, he said.

“It has the potential to really bring you down,” he said.

If your condition does deteriorate, it’s best to rest until the symptoms go away, Nieman said.

“Then, gradually get back into the routine,” he added. “Relapse can be common if you get back too quickly and push hard.”

In rare cases, exercising intensely while you’re sick, or even shortly after you’ve recovered, could lead to new or lingering symptoms like exhaustion or unexplained pain.

Researchers believe this phenomenon is similar to how some people develop long Covid-19 or chronic fatigue syndrome (also known as myalgic encephalomyelitis, or ME/CFS), which are illnesses that can develop after an acute infection.

This article originally appeared in The New York Times