When to Start Working Out After Being Sick

It’s the winter so let’s talk about another winter related topic.

In general, there is some degree of controversy over if you should work out when sick, and if so should be be modifying your workouts depending on the degree of illness.

Basic physiological processes

What happens if we workout while sick?

Stress of the workouts creates the microtears in our muscles. These microtears from the stress are a normal process of damage and repair. The body uses inflammation to signal and start to repair the damage caused by working out. Inflammation is obviously initiated and maintained by the immune system until all tissues are repaired and strengthened against the stress that was placed on the body.

In addition, stress from activity especially sustained activity elevates cortisol levels. Cortisol helps mobilize the body’s supply of fat and glucose to provide fuel for the muscle, but it is an anti-inflammatory and immunosuppressive. For example, cortisone is a derivative of the same class of drugs, the glucocorticoids, and is used therapeutically to reduce pain and inflammation in specific areas of the body. Our immune system is the way that our body fights infections and other pathogens that make us sick.

You can see how diverting the immune system away from fighting infections towards repairing muscles may be problematic. I have seen it many a times where someone is sick and decides to workout and they get even sicker. Similarly, you can even almost be over an illness and workout a couple of days after it has gone away and then it will come back.

This is similar to antibiotics. When doctors prescribe antibiotics they tell you to continue to take them for the whole amount of weeks and not to stop even if you feel better. Likewise, even if you do not feel sick anymore the body is still fighting the last remnants of infection within your body. So when you subject it to heavy stress from working out or trying to come too quickly to exercise it may depress the immune system such that the infection comes back. Sometimes more strongly than the first time.

Regarding the intensity of workouts while sick

The higher the intensity of the workout, the more probable it is for higher damage to the muscles.

Thus, resistance training or sprinting or high intensity interval training or circuit training will be poor choices to do while sick. Resistance training can be fine if there is less muscle damage such as working in lower repetition ranges for strength or working in some of the higher repetitions for endurance as long as the volume is not too high. It is the moderately-heavy weight at moderate repetitions (e.g. the bodybuilding repetitions of 6-12) that tend to do the most muscle damage.

There is the common saying that you can workout if its just a head cold, but do not workout if the infection is in the throat/chest or lower.

I find this to be true as long as intensity is kept down. Chest illnesses such as pneumonia, bronchitis,etc. tend to a bit more potent than head colds. However, the caveat is that lying down and totally resting does actually foster these illnesses a bit to an extent which is why you see a lot of nosocomial infections (illnesses you get from being in a hospital usually on bed rest).

Thus, lying around doing nothing may not actually be as beneficial when sick than at least some type of movement aside from working out. Getting up and moving around to get blood flowing and doing some deep breathing to help mobilize secretions especially if you are coughing a lot is a good idea.

Generally, if you do decide to workout then keep the workout light. Perhaps a warm-up and see how you feel or a light run may work well. If you tend to overdo it once you get started it may be better to avoid working out altogether until your sickness is over.

Any exercise that you do should leave you feeling better than you started. If you start to feel worse then it may be time to give it up for the day and rest. Remember, our muscles and bodies recover when we rest, and it is exactly the same for illnesses.

Light activity like walking or cardio is very helpful, especially if you can do it outside in the sun. It will help get the blood flowing in the body and stimulate lymph drainage and movement which improves the immune system. If anything, I would not risk trying to do a strength or hypertrophy workout while sick because it could set you back. Light activity, especially in getting the heart rate up but not too intense, is a good thing to do.

How to work yourself back into exercise

Work slowly back if you are used to high intensity exercises. For a cold, a 1-2ish week buffer between getting back to full exercise is likely good.

For more severe illnesses such as influenza or pneumonia, I would take at least 2-3 weeks after all of the symptoms have subsided to work back into things with full intensity. The problem with going back to high intensity right away is that even if all of the symptoms have gone away there is still bacteria or viral loads in your body, just not enough to make you symptomatic. So high intensity exercise can actually depress your immune system enough to make the illness come back, sometimes even stronger than ever. Thus, it is best to be conservative with this.

If you’re using a typical 3x a week type of exercise schedule, start with about 20-30% of your typical full workouts, and ramp up by 10% until after about 2-3 weeks you will reach 100%. Best to be conservative than get an illness again and be out another couple weeks if not more.

Things that may help

  • Sleep is obvious. The body can devote full attention to fighting off infection when sleeping.
  • Good nutrition. Our bodies will tend to suppress appetite when we are sick, but food is good for the calories to supply energy for our body to fight the infection. I do not know where the myth(s) came from that ginger ale or other really sugary foods are good during sick, but they are obviously not whether sick or well. Edit: someone has suggested ginger root.
  • Eat healthy. Fruits and vegetables are good choices. If you have a low appetite, try to eat but don’t make yourself nauseous.
  • Vitamin D is a potent immunomodulator and increases amounts of the anti-microbial peptide cathlicidin, defensins 1 and 2, and T-cells which will help fight infection.

Most people are deficient, and stay indoors when sick so this is definitely a factor to look at especially since most illnesses occur during the winter when there is less sun out. Sunscreen typically blocks UVB radiation which can make people deficient even during summer.

Get out in the sun if possible when you’re sick. You may not feel like it, but it will help your body fight the infection.

  • There is some support for zinc supplementation. However, those who supplemented with Zinc also had higher incidences of side effects. If you are deficient in zinc, which most people are like with vitamin D, then this can be a good option to pursue as well.

Things that won’t help

Vitamin C. Yes, the studies show that vitamin C does absolutely nothing for fighting colds or illnesses. However, there are still some adamant believers that it is the vitamin C that keeps them from getting sick or helps them recover from sickness earlier. More power to you if you believe this, but the skeptics should not bother. There are many reviews of which I have listed two: one, two

A quick search through pubmed shows that it may reduce symptoms very slightly at best. Don’t bother supplementing vitamin C for colds or upper respiratory tract infections.

Edit: there seems to be some evidence presented by a commenter (Ole) that very high dose vitamin C to tolerance in particular bad infections. Thus, it may help supplement your body’s natural vitamin C production to increase ability to sop up the oxidation from the immune system as it battles with the infection. Therefore, if you have a particularly bad illness it may be a decent idea to supplement which may help aid the immune system. How much I am not sure though.


If you work out in a gym you do not want to be infecting people around you. This is not good gym etiquette. Please stay home and let yourself rest and recover.

  • For sickness, getting up and moving about is good. Perhaps a light workout such as a warm up or light run is fine to get blood flowing and the lungs mobilizing secretions.
  • Be careful about high intensity exercise of any kind during and when recovering after an illness. It may make you sicker.
  • Be conservative about coming back from an illness. If you go too intense too soon you can relapse and go through the same illness again with possibly worse symptoms.
  • For fever, sleep and rest.
  • Vitamin D may be beneficial to help fight illnesses especially if you are deficient from not being outside a lot or it being the winter. Get out in the sun. Supplement if necessary.
  • Zinc supplementation can also be potentially beneficial.

Use your knowledge to come back from sickness and work back into exercise slowly but surely.

This article was originally published January 23rd, 2012 on Eat Move Improve. Updated Feb 2017. 

Questions about articles may be addressed to the Overcoming Gravity reddit.

Disclaimer: Any information contained on this site should not be misconstrued as professional medical advice. Always consult your appropriate medical professional before using such information. Use of any information is at your own risk.

Author: Steven Low

Steven Low, author of Overcoming Gravity: A Systematic Approach to Gymnastics and Bodyweight Strength (Second Edition), is a former gymnast who has performed with and coached the exhibitional gymnastics troupe, Gymkana. Steven has a Bachelor of Science in Biochemistry from the University of Maryland College Park, and his Doctorate of Physical Therapy from the University of Maryland Baltimore. Steven is a Senior trainer for Dragon Door’s Progressive Calisthenics Certification (PCC). He has also spent thousands of hours independently researching the scientific foundations of health, fitness and nutrition and is able to provide many insights into practical care for injuries. His training is varied and intense with a focus on gymnastics, parkour, rock climbing, and sprinting.