This habit works wonders for immunity

Author: Kate Cross

Looking for a versatile, inexpensive, easily accessible way to improve your immunity? Researchers suggest turning to your own body. Specifically, your active body.

It’s perhaps of no surprise that exercise does wonders for the immune system.

According to University of Arizona immunobiology expert Richard Simpson, physical activity has an immediate effect on this “highly intricate network of cells and molecules designed to keep [us] free from infection and disease”.

Research has even shown that exercise can offer some protection from illnesses, such as influenza, the common cold and various herpes viruses, he writes in a blog post for the American College of Sports Medicine.

But how?

Simply put, “the immune system has three main lines of defence [and] exercise helps maintain the normal function of each of these”, state University of Bath academics Drs James Turner and John Campbell in The Conversation. 

The three lines of defence, they write, are “physical barriers” (e.g. the skin); “‘innate’ (or natural) immunity”, which is comprised of cells; and “‘adaptive’ (or memory) immunity”, comprised of more cells. Exercise appears to work magic on each of these.

For example, the academics cite research showing that skin wounds heal quicker in those who are active rather than sedentary. “Faster wound healing reduces the risk of bacteria and virus entry,” they state.Adds Dr Simpson: “Each bout of exercise, particularly whole-body dynamic cardiorespiratory exercise, instantaneously mobilises literally billions of immune cells, especially those cell types that are capable of carrying out effector functions [i.e. bring about change], such as the recognition and killing of virus-infected cells.”

But I’ve heard extreme exercise can suppress immunity …

There is a commonly held belief that strenuous, prolonged physical activity – think running marathons – momentarily suppresses the immune system, making the person temporarily more prone to infection, according to Drs Turner and Campbell. 

However, the exercise-immunology researchers state there isn’t enough supportive evidence.

In a 2018 Frontiers in Immunology paper, they wrote: “It is a misconception to label any form of acute exercise as immunosuppressive, and, instead, exercise most likely improves immune competency across the lifespan.”

What does this mean for COVID-19?

Unfortunately, authorities don’t know for sure … yet. In his blog post (dated March 30), Dr Simpson says post-COVID-19, he envisions “a large body of exercise immunology research”.

Indeed, researchers from the University of Virginia have already suggested that regular cardiovascular exercise might help lower the risk of acute respiratory distress syndrome, a serious complication of COVID-19.

For now, Dr Simpson says while regular exercise won't necessarily prevent coronavirus infection, it may help reduce the virus’ harmful effects, improve symptoms, hasten recovery and minimise the spread. Of course, he adds “this is merely my intuition” and “currently, the greatest risk of COVID-19 infection is exposure”.

Known and potential benefits of exercise aside, it’s crucial common sense prevails in the face of the pandemic. This means maintaining proper hand hygiene and cough etiquette, self-isolating if you are unwell, not smoking, physically distancing yourself from others and not touching your face, according to the World Health Organization.

Don’t forget sleep, diet and contact

In your quest to get or stay fit remember regular exercise is one piece of the fascinating immune system puzzle. 

Writes physician Dr Kate Gregorevic for The Age: “Getting enough sleep and exercise, eating well and maintaining social connections are all excellent for mental and physical wellbeing and optimising immune function.”




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