top of page


  • A complex network of cells and proteins that defend the body against infection. Every day we come into contact with countless substances foreign to our body. Its the job of our immune system to identify and, if necessary, eliminate anything unfamiliar and unwelcome in our bodies.

  • Think of our immune system like an army - each troop has it's own specific job or function. Together our organs, cells and chemicals work collectively to protect the body and fight infections.

  • Our immune troops include:

    • White blood cells - responsible for the destruction of infectious agents.

    • Antibodies - to identify and neutralise foreign objects.

    • Complement system - the surveillance system of the body.

    • Lymphatic system - to maintained fluid balance and drainage.

    • Spleen - responsible for blood filtration.

    • Thymus - creates white blood cells.

    • Bone marrow - helps to produce immune cells.

exercise for immunity


When our body and immune system are functioning optimally, the immune system recognises invaders, such as bacteria, viruses and fungi as well as abnormal cells. It then responds by fighting the invasion, helping you feel well again.


Unfortunately it is possible, and not uncommon, for immune systems to be compromised or not function optimally. This can lead to:

  • Increased risk of getting sick

  • Increased length of sickness

  • Increased intensity of sickness

  • Abnormal immune responses

WHAT CAN WE DO TO SUPPORT OUR IMMUNE SYSTEM? Our health and immune system function are affected by the 5 pillars of health. These are:
  1. Sleep

  2. Nutrition

  3. Activity

  4. Stress

  5. Environment (physical and social)

How we approach each of these pillars affects the overall health and function of our immune system. In this article we are focusing on the third pillar, activity (exercise) in supporting our immune system.

EXERCISE AND THE IMMUNE SYSTEM "Regular physical activity helps to improve the immune system, while helping to prevent respiratory diseases and thus protect against infections, such as COVID-19" (Silveira et al, 2021).

exercise and immune system

The activity pillar supports our immune system in a range of ways as outlined below:

1. Direct impact on the immune system include:

  • Increases immuno-vigilance and improves immune competence.

  • Decreases inflammatory responses and stress hormones.

  • Increases and optimises lymphocytes, NK cells, immature B cells and monocytes.

Simply put, exercise can help improve your immune systems detection systems and how well they fight off illness.

2. Reduced risk of complications - performing regular physical activity and having a good baseline level of fitness is also shown to reduce our risk of complications when we do become ill. "Regular exercise can reduce around two dozen physical and mental health conditions and slow down how quickly the body ages" (Alford, 2010).

3. Creating a strong baseline - When we are unwell, a large amount of our energy is redirected towards our immune system in resting and recovering. If you've ever tried to return to exercise after being unwell you may have noticed everything feels just that little bit harder. Since we're resting more and moving less when we're unwell, it is not uncommon for us to see decreases in strength and aerobic capacity.

Having a high baseline level of fitness and strength is vital to our recovery. Decreases in fitness can be inevitable with illness, but if we have a higher starting point, post illness we are able to return to higher levels of function faster. In short, a week of inactivity will effect someone much less if they have a higher baseline of health.

4. Returning to exercise after illness - Unfortunately infection and illness can have carry over effects, including lethargy, fatigue, lingering cough, muscle weakness and poor exercise tolerance. Depending on the severity of the illness, your return to exercise will need to be graded (start slowly and build up over time).

Exercise after covid

A great resource outlining return to exercise can be found here. Although it was specifically designed for post COVID19 infection, much of the content in the section Graded Return to Physical Activity', is applicable to recovery after many common illnesses.

If you would like advice about how to safely return to exercise after an illness, please contact us on 5456 1599 and book an appointment with a specialised exercise physiologist.

bottom of page