This is a question that comes up quite often, especially this time of year.  The answer depends on several factors, including what type of illness you have and what type of exercise you are doing.  Let’s talk today about the role that exercise plays in your immune response to illness and whether that can be helpful or harmful when you are ill, as well as how a routine exercise program impacts your susceptibility to infection.

Can routine exercise decrease the chances of getting sick?

The answer is a definite yes, but there are some exceptions.  Research indicates that people who participate in moderate exercise on a regular basis (approximately 150 minutes per week) have significantly fewer respiratory infections than people who are sedentary.  This includes colds, flu, sinus infections, and other respiratory infections.  There are positive immune changes that take place during each bout of moderate physical activity, which translate to this protective benefit.

On the other hand, people who are pushing beyond normal exercise limits, such as regularly participating in high intensity exercise or exercising for excessive time periods, have significantly more respiratory infections than people who perform moderate exercise.  This includes people who are participating in high intensity work outs for more than 90 minutes at a time on a regular basis, such as marathon runners.

What if you already have a cold?  Should you exercise?

In general, mild to moderate exercise is usually fine when you have a mild upper respiratory illness, such as a cold.  Exercise can even help to temporarily open your nasal passages and relieve some congestion.  However, there are times when exercise may cause more harm than good.

Here are some general guidelines to consider when deciding whether to exercise when you are sick:

• Do not exercise if you have the following symptoms:
  • Fever, body/muscle aches, or fatigue
  • Chest congestion, wheezing, or a bad cough
  • Upset stomach, nausea, vomiting
• You can exercise if you only have the following symptoms:
  • Runny nose, head or nasal congestion, sneezing, minor sore throat

Some people like to use the distinction “above the neck” or “below the neck.”  If your symptoms are all above the neck, it is ok to exercise, but if you have symptoms below the neck, you should not exercise.  I usually say, if you feel miserable, you should take a few days off from exercise.  If your symptoms are bothersome, but not making you feel miserable, go ahead and exercise.

If you do want to exercise when you are sick, here are some things to consider:

• Reduce the intensity and length of your normal work out; maybe go for a walk instead of a run.
• Consider doing some indoor exercise, rather than exercising outdoors in winter weather conditions.  If the weather is not harsh, the outdoor air might do you some good.
• Listen to your body.  If you get tired or your muscles start hurting during your workout, you should stop the workout.  The next day, try something less strenuous.
• If you start coughing or wheezing during a workout, stop the workout.

If you do take a few days off from your regular exercise routine while you are sick, this should not have any adverse effect on your exercise performance.  As you start to feel better, gradually get back into your exercise routine.  Start at a lower intensity and pace, and gradually increase to your normal routine.  Within a few days to a week, you should be back to your normal workout.

If you have any more questions just Ask Hanna, our health advisors are here to help.

Dr. Anita Bennett MD – Health Tip Content Editor
Image: ©Shutterstock / baranq