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  • Writer's pictureCrucial Rehab Team

Covid-19: How exercise can improve your immune system.

With the presence of an unseen, wildly spreading virus roaming in our midst, staying healthy seems to be the most crucial at this point, apart from getting vaccinated and following basic SOPs. Keeping our bodies in tip top condition is highly relevant to maintaining a healthy immune system. Though this does not deter us completely from contracting the virus, it reduces the severity of the infection. Among the many factors in doing this, I’ll be focusing on the effects of exercise.

Signs of a weak immune system

Though coming down with a cold or flu happens approximately 2-3 times per year to an average adult, getting sick every now and then may indicate something more severe. Here are 5 signs that your immune system is signaling for help:

- Frequently catching colds and viruses which normally last for some time

- Experience stomach aches easily

- Wounds tend to heal slower than most people

- Frequently has infections such as urinary tract infection (UTI), pneumonia, sore throats etc.

- Often feel tired and sleep deprived

Factors that can lead to these signs normally form an unhealthy lifestyle, which include:

- High stress levels

- Lack of quality rest or sleep

- Poor nutrition & dehydration

- Lack of physical exercise

Our antibodies also known as immunoglobulins which are infection fighting proteins are important immunity mediators. An unhealthy lifestyle can often curb the formation of these antibodies and increase the risk of falling sick. Since exercise triggers our endorphins (happy hormones), a lack of physical movements can often lead to one feeling sluggish or even depressed.

How can exercise help?

Moderate intensity exercise increases and allows faster circulation of antibodies

Moderate physical exercise has been shown to provide an immediate temporary boost in the production of macrophages (cells that attack bacteria). It also promotes faster circulation of these cells throughout the body to allow efficient eradication of viruses. Studies have shown that during moderate and vigorous-intensity aerobic exercise bouts of less than 60 min duration, the antipathogen activity of tissue macrophages occurs in parallel with an enhanced recirculation of immunoglobulins, anti-inflammatory cytokines etc. These transient, exercise-induced increases in selective lymphocytes enhance immunosurveillance and lowers inflammation. The immune system generally returns to normal after a few hours post-exercise but studies have shown that consistent, regular exercise on a near daily basis proves to have more long-term immune effects. Examples of moderate intensity exercise includes brisk walking or cycling for 20 minutes.

HOWEVER, it is important to note that TOO MUCH intense exercise can also reduce immunity temporarily. A bout of high intensity endurance exercise that exceeds 90 minutes can make athletes vulnerable for 72 hours post exercise. It was found that a hormone called cortisol is produced in high levels during long periods of intense exercises and this in turn suppresses the immune system. This same hormone is also triggered by high stress levels in the body. Hence, proper recovery is vital if intense exercise was done.

Improves lung function

Covid-19 is an acute respiratory infection which not only dampens our immune system but also affects our lungs. Exercise helps maintain and also increases our lung capacity and function. When performing moderate to high intensity exercises, our heart rate and breathing rate increases. This allows deeper breathing and increases movements in the lung tissues. Being able to breathe deeply also clears our airways to prevent pooling of bacteria in the airways.

In a nutshell, exercising regularly in a week even if it is only for 15 minutes can not only keep you healthy but also safer.


1. Ahmed ET (2012) Exercise and Immunity. J Nov Physiother 2:e115. doi:10.4172/2165-7025.1000e115

2. Da Silveira, M. P., da Silva Fagundes, K. K., Bizuti, M. R., Starck, É., Rossi, R. C., & e Silva, D. T. D. R. (2021). Physical exercise as a tool to help the immune system against COVID-19: an integrative review of the current literature. Clinical and experimental medicine, 21(1), 15-28.

3. Nieman, D. C., & Wentz, L. M. (2019). The compelling link between physical activity and the body's defense system. Journal of sport and health science, 8(3), 201-217.

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