In 2018 an article was published in the journal Frontiers in Immunology that attempted to debunk some of the myths around exercise and the immune system.
The paper focuses on the fact regular exercise can help reduce the incidence of viral and bacterial infections. It was once thought that a single exercise session could supress the immune system. We now know that this is wrong. What is really happening in our bodies when we exercise is far more fascinating!
So why did we think that exercise could reduce our immune response to things like viruses? Scientists found that when we exercise the level of immune response in the mucosal membranes (salivary IgA) falls. There was also a reduction in the amount of lymphocytes (white blood cells that are key to our immunity) in the first couple of hours after exercise. So it was supposed that exercise supresses our immune response and puts us at risk of viruses.
We have since found out that the opposite is true. The white blood cells were in fact being distributed to peripheral tissues and were in fact representative of a “heightened state of immune surveillance” . Exercise actually stimulates the immune system.
If we keep the length of the exercise period to moderate amount (no ultramarathons please folks) then our bodies can respond. Both younger and older people can benefit exercise, and the authors of the paper say that “frequent participation in exercise across the lifespan may lead to immune benefits, even in older age”.
There is even more good news when it comes to exercise and immunity. Scientists now understand that exercise can prevent our immune system from aging. Who doesn’t want that?
Exercise can seem like a real chore and it can be hard work starting to be more active but the benefits are huge. When we go outside for a brisk walk or run our immune systems are primed to protect us. Exercise really is your immune systems best friend.
You can read the full paper here (https://www.frontiersin.org/articles/10.3389/fimmu.2018.00648/full)