We spoke to doctors to learn more—here’s what to keep in mind before you hit the treadmill with a stuffed-up nose.

What Happens to Your Body When You’re Sick

First things first: You should never work out when you’re sick with something serious, like the flu. But a mild cold can be a little more confusing. The common cold is a viral infection of the upper respiratory tract, which includes the nose, throat and sinuses. The most common symptoms are runny nose, congestion, sneezing and coughing. And most people recover from a cold within a week or two without any complications, Dr. Kellie K. Middleton, MD/MPH, an Atlanta-based orthopedic surgeon, explains. “Your body’s response to the common cold or any virus is an immune response to help fight the virus, so your body signals to your immune system to send out cytokines or messengers that help recruit other immune cells and antibodies,” says Dr. Purvi Parikh, MD. “As a result, blood flow to the area where your virus first enters increases and blood vessels dilate to bring these immune cells there to help stop the virus from sticking around. This is why we get headaches, nasal congestion, runny nose and cough—it’s our immune system in action.”

How Does Exercising Affect Immune Function During Sickness?

Exercise has been shown to boost immune function and help the body fight off infections. However, strenuous exercise can also temporarily lower immunity, which is why it’s important to listen to your body when you’re sick, Dr. Middleton states. Working out also induces an immune response with increased blood flow and temporary stress on the body. In the short run, your immune system is taxed and stressed even when not sick, but even more so when you are already fighting a cold or illness, so one must be careful, Dr. Parikh explains.

If You’re Sick, Here’s When to Work Out and When to Rest

Doctors say to follow the “above-the-neck” rule. “A general rule I use when deciding whether to exercise while sick is to go ahead if the symptoms are above the neck and rest if they are not,” says Dr. Leann Poston, MD, MBA, MEd. “If you have a runny nose, congestion or a minor sore throat, go ahead with exercise if you feel up to it. Avoid public places so you don’t spread your germs. If you have a fever, fatigue, muscle aches or chest symptoms, rest until you feel better and then gradually resume exercise.” Dr. Middleton agrees that if your symptoms are above the neck—such as a runny nose or congestion—then it’s generally safe to exercise. However, if your symptoms are below the neck (such as a cough or body aches), then it’s best to rest and allow your body to recover. Additionally, if you have a fever, it’s best to wait until it has resolved before working out. “Mild or moderate low-impact exercise when you are sick is OK and may even help you feel better, but only if you have no fever and no symptoms below the neck. For example, no cough, wheezing, or shortness of breath, muscle aches or fatigue,” says Dr. Parikh. “If you exercise when you are febrile, having trouble breathing, or are very fatigued or with muscle aches, it can be quite dangerous as you are already stressing an over-stressed body." If your symptoms are above the neck and you do decide to work out while you’re sick, it’s important to maintain good hygiene, especially if you’re sick. This means wiping down equipment before and after use and showering as soon as possible after your workout, Dr. Middleton adds. Next up: When It Suddenly Hurts When You Swallow, You Know a Sore Throat Is Coming on—Try These Natural Remedies to Beat It

Sources

Leann Poston M.D., M.B.A., M.EdKellie K. Middleton, MD/MPH, an Atlanta-based orthopedic surgeonDr. Purvi Parikh