It's "summer cold" season, and it's here to put a damper on your training schedule. If you’ve ever tried to run while suffering from a cold, you know it’s no walk (or run) in the park. But is it bad for your health? Not always. Ultimately, it depends on your symptoms, according to Dr. Anthony Hackney, Ph.D., professor of exercise physiology & nutrition at the University of North Carolina, Chapel Hill.
Hackney, who works with professional athletes, says the first rule of running while sick is obvious: Don’t run if you have a fever. Especially if your illness is in early days, a high temperature could signal that you’re actually experiencing early flu symptoms, which would be much more serious.
Hackney’s other rule of thumb is a little more complicated. He says it’s usually okay to go out for a jog if your cold symptoms are affecting you from the neck up. If you’ve got the sniffles or a sore throat, it shouldn't be a big deal to run. But if you’re coughing a lot and you can tell the cold has spread into your chest — say, you’re hacking up phlegm — it’s generally better to rest up before you hit the pavement. “If you’re running and you’re congested in your chest, it’s harder to get air in and out,” Hackney says. “You run the risk of it being more difficult to get oxygen into your blood. This is going to mean you’ll have to work a little bit harder when you run, which will make you a little more fatigued.” If you’re fatigued, it’s harder for your body to fight off the cold.
Hackney also points out that if you’re exercising intensely, you’ll have what doctors call transient immunosuppression. In human speak, that means your immune system is not working as well as it should after a difficult sweat session. This is an added layer of bad news, as your system is already trying to fight off your cold. “If you have immunosuppression, that means you might get sick from things you wouldn’t normally get sick from,” Hackney says. This could make you sicker when you’re already sniffly and miserable.
One way to avoid this immunosuppression is to not exercise as hard as you normally would. Take a few miles off your run, or slow your pace.
For what it’s worth, I asked Cleveland Clinic’s Dr. Donald Ford, a family medicine specialist, if running with a cold was ever okay, and if the adrenaline from exercise could help fight off a cold. His response was: “No, no, no.” Some doctors are more conservative than others.
The bottom line is this: As Hackney puts it, run at your own risk, and take it easy on your body.
“When you get a cold viral infection, your body is already putting stress on itself from a health perspective to fight it off,” Hackney says. “If you’ve already got one stress, don’t add too many more on top of that.”