Exercise and Illnesses


Does an illness need to derail your exercise plans?

Should I exercise when I am sick?  This is not an exact answer.  But, I will do my best to provide an answer.   

What type of illnesses are we discussing?

  • allergies
  • colds
  • coughs
  • ear infections
  • sinusitis
  • tonsillitis
  • throat infections (sore throat)

Whether you should exercise depends not he several issues:

  1. Benefit
  2. Risk to others
  3. Risk to exerciser 

This is a classic risk versus benefit.  If the res to yourself or others is too great, you should avoid the gym.  For example, if you have influenza, this is extremely contagious and not everyone is vaccinated.  If you are confirmed to have it, you should stay home till a provider says you are good to return to the gym. 

I usually look at it this way, if I would take medication and go to work, I can probably work out but I would do so with a little less intensity.  You are probably ok with it is just a common cold, but take your temperature.  I have heard many exercisers say they are sweating out a fever.  This is not good behavior and you are better avoiding the gym if you have a fever.

Exercising vigorously when you are dehydrated or have a fever makes you at a higher risk of a head injury or illness.  Your body has difficulty regulating temperatures and will overheat.  This can result in a permanent injury.  This will hasten your recovery and potentially make your illness worse.

Pills with a Thermometer
Figure 1: Pills with a Thermometer

If you have gastroenteritis (nausea and/or vomiting), I would avoid the gym.  You don’t want to spread the illness.  It can spread rapidly from person to person and you need to rehydrate.  It also makes you dehydrated at a higher risk of heat injury.  See the paragraph above.  Heatstroke is no joke and it can happen in the winter months.  Running a marathon when you are recovering from an illness is probably ill-advised.  

I also look at the severity of the illness.  I would not exercise if you just had a heart attack or any other life-threatening illness, but the common cold should be ok for exercise.  Try a gentle walk and see if you tolerate it.  I would not exercise heavily if I were recovering from a cardiac event, head trauma, or influenza for example.  You ahem to use a little common sense and if that is a weakness for you, call your provider.  

Common Cold
Figure 2:  Allergies or Common Cold

So how do you tell if a common cold is a common cold?  Common colds are centered in your head and neck and not in the chest.  If you have a cold, you will have nasal congestion, sore throat, chill, cough, body aches, and headache.  If you can breathe through your mouth without difficulty, it is probably a common cold.  If you have uncontrolled bouts of coughing and are short of breath through your mouth, consider discussing exercise with a provider or making an appointment.  

What type of exercises should I do when I am ill?  I recommend less strenuous exercises such as walking, stretching, slow swimming yoga, isometrics.  I recommend that you avoid heavy weight lifting, running, sprints, team sports, and any exercise outdoors in the heat.  If it raises your heart rate above 120 when you are not ill, avoid them.  Exercise helps the immune system​​[1]​, but extreme exercise weakens the immune system and makes the illness worse, or since you are already stressed, it can make the body more susceptible to another illness.  

How long does a cold last?  The textbook answer is 10-14 days, but you should be improving in 3-5 days.  The key is returning to exercise when you feel able, but don’t rush yourself.  You may feel better exercising but might feel worse the next day and make the illness last longer

Should I do anything special if I go to the gym or work?  Yes, wash your hands and clean the equipment diligently to avoid infecting others.  Other folks at the gym do not want you to share your bacteria and viruses.  Carry hand wipes or sanitizer to treat your hands after a sneeze, cough, or touch your mouth, nose, or eyes.  

How do I stop from getting a cold?  Colds are spread by hands usually.  Someone placed the virus through a sneeze or cough on the surface and you touch the surface.  It is not intentional but you get it nonetheless.  The way to prevent eating it is to wash your hand when you around ill people and to avoid touching any moist areas such as your nose, mouth, or eyes.  Also, the best news is, exercise, and getting plenty of sleep will help prevent you from catching a cold in the first place​[2]​,​[3]​.  

As with anytime you exercise, if you are new to exercise after an extended period of sedentary life style, consider talking to your provider and getting suggestions.

Infographic:  Precision Nutrition has a great infographic on common colds and exercise​[4]​.


  1. [1]
    N. Walsh et al., “Position statement. Part one: Immune function and exercise.,” Exerc Immunol Rev, vol. 17, pp. 6–63, Jan. 2011 [Online]. Available: https://www.ncbi.nlm.nih.gov/pubmed/21446352
  2. [2]
    D. Nieman, D. Henson, M. Austin, and W. Sha, “Upper respiratory tract infection is reduced in physically fit and active adults.,” Br J Sports Med, vol. 45, no. 12, pp. 987–92, Sep. 2011, doi: 10.1136/bjsm.2010.077875. [Online]. Available: https://www.ncbi.nlm.nih.gov/pubmed/21041243
  3. [3]
    D. Brunelli, K. Caram, F. Nogueira, C. Libardi, J. Prestes, and C. Cavaglieri, “Immune responses to an upper body tri-set resistance training session.,” Clin Physiol Funct Imaging, vol. 34, no. 1, pp. 64–71, Jan. 2014, doi: 10.1111/cpf.12066. [Online]. Available: https://www.ncbi.nlm.nih.gov/pubmed/23848167
  4. [4]
    “Exercise When Sick? Infographic,” Precision Nutrition. [Online]. Available: http://www.precisionnutrition.com/working-out-when-sick-infographic. [Accessed: 15-Oct-2016]
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About the Author

I am a family physician who has served in the US Army. In 2016, I found myself overweight, out of shape, and unhealthy, so I made a change to improve my health. This blog is the chronology of my path to better health and what I have learned along the way.

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