Should You Exercise When You're Sick?

Energy Level

Your energy level is one of the best indicators of whether or not you should be working out. If you're tired and feel rundown, you should let your body rest and recover before you begin exercising again.

If you have a simple cold and your energy level is fairly normal for you, it's probably fine to exercise.

However, intensity is something to consider. You may be able to handle a mellow yoga class but not an advanced cardio class.

The "Neck Check"

Despite the shortage of research, healthcare providers do have some common guidelines they use to advise their patients who worry about hitting the gym when they're under the weather.

One such guideline, based a 1996 study, is called the "neck check." Basically, if your symptoms are all above your neck (sniffles, sneezing, etc.), you're probably fine to work out. If they're below your neck or systemic (vomiting, coughing, fever, body aches, etc.), it's probably best not to exercise.

That advice isn't clear-cut or supported by further study, however, so it helps to know more about specific symptoms and how they could impact you while working out.

Fever

This one symptom comes with crystal clear advice: If you have a fever, stay home. Research shows that strenuous exercise with a fever can make you sicker—so much that it increased the likelihood of death in animal studies.

The reasons for that are many:

• Fever increases fluid loss and dehydration.
• Exercise in addition to fever can raise your body temperature to a dangerous level.
• Fever saps your energy and lowers your muscle strength and endurance.

It’s usually not a hard decision to forgo exercise when you have a fever—your bed is likely calling your name much louder than the gym.​

Cough

Coughs can be a little more tricky than fevers when it comes to deciding whether or not to exercise.

According to conventional advice, the neck check applies:

• If you just have an occasional dry cough, like a tickle in your throat, then you're probably fine to continue your exercise routine.
• If your cough is frequent or productive (you're coughing up phlegm) and interferes with your ability to breathe properly when your heart rate is up, you should consider resting until the cough has improved.

When in doubt, check with your healthcare provider.

Congestion/Runny Nose

Congestion and runny noses (those "above the neck" symptoms) generally aren’t reason enough to stay away from your workout routine. But if you have significant difficulty breathing due to the congestion, you may want to tone it down a bit until your condition improves.

Some people base their decision on the color of their mucus, but that's not a good gauge of how sick you are. Just because it's yellow or green doesn't mean your infection is bacterial. Viral illnesses can cause discolored mucus just as easily as bacterial ones.

"But I'm an Athlete"

If you work out all the time and you're in great shape, you might think you're an exception—that your body can handle the stress of exercise even though you're ill.

Again, research doesn't have definitive answers, but consider these facts:

• Much of the research that has been done on exercising while ill has been done on athletes, so the suggested restrictions definitely apply to you.
• Exercising while ill can increase your risk of an injury, and an injury is likely to take you out of the game for a lot longer than a passing illness.

A Word From Verywell

Whether you should exercise when you're sick is really an individual decision based on your specific symptoms and how you feel. If you don't exercise regularly, it's probably best to wait until you're healthy before starting a fitness routine. If you aren't sure, check with your healthcare provider.

It is also interesting to note that some research suggests people who get regular exercise are less likely to catch colds and get sick in general. So, when you're back to 100%, consider that one more bit of motivation to get regular physical activity.