Exercise has long been recognized for the numerous health benefits it provides, including the ability to reduce inflammation in the body. Inflammation is a normal immune response that aids the body in fighting infections and repairing damaged tissue. Chronic inflammation, on the other hand, can contribute to the development of a variety of diseases, including cardiovascular disease, diabetes, and certain types of cancer. Researchers are still trying to figure out why exercise helps with inflammation.
Researchers have long known that moderate exercise improves the body’s response to inflammation, but the why has remained unknown. New research from York University on a mouse model suggests that the answers may be found in the production of macrophages, which are white blood cells responsible for killing infections, healing injury, and acting as first responders in the body.
“Much like training your muscles, we found that moderate-intensity exercise ended up training the precursors of those macrophages in the bone marrow,” says Faculty of Health Associate Professor and York Research Chair Ali Abdul-Sater of the School of Kinesiology and Health Science. “Exercise does this by changing the way those cells breathe, essentially how they use oxygen to generate energy, and then changing the way they access their DNA.”
Inflammation is amazing; it’s a critical part of our normal immune response. What we’re concerned about is excessive inflammation. Heart disease, diabetes, many cancers, and autoimmune diseases all begin with an inappropriate inflammatory response.Abdul-Sater
While many studies look at temporary immune system boosts following exercise, this study, published in the journal AJP-Cell, discovered these changes occurred even a week later, indicating that the changes were long-term.
We often hear about inflammation in the body in terms of its negative effects, but inflammation is the body’s response to infection and other stressors, and some level of inflammation is both necessary and desirable.
“Inflammation is amazing; it’s a critical part of our normal immune response,” Abdul-Sater says. “What we’re concerned about is excessive inflammation. Heart disease, diabetes, many cancers, and autoimmune diseases all begin with an inappropriate inflammatory response.”
He says it is around the six-to-eight-week mark into the exercise regimen where changes really became apparent, compared with sedentary mice. “There’s a lot of rewiring that’s taking place in the circuitry of how the cells breathe, how the cells metabolize glucose, how the cells then accessDNA. So all that just takes time.”
According to Abdul-Sater, because the inflammatory response is so ancient, this aspect of the immune system is generally very similar across mammals, and he expects the research to be applicable to humans. In the next stage, Abdul-Sater and his university colleagues will collect immune cells from human volunteers who will perform a variety of exercises to determine which workout routines are most effective in balancing the inflammatory response. They will also investigate inflammation in mice in more complex infectious diseases, such as COVID-19, and autoimmune disease, where overactive inflammatory responses result in poor outcomes.
“People who became seriously ill from COVID-19 went into what is known as a cytokine storm, essentially, they released this massive number of cytokines, those mediators produced by inflammatory cells, which then cause that accumulation of fluid in the lungs.”
While the findings that exercise is beneficial are not surprising, Abdul-Sater hopes that by identifying the underlying mechanisms of the beneficial effect, this knowledge can be put to good use.
“The thing about humans is that there is no intervention that will work on everyone. We already knew that, but this study suggests that moderate and consistent exercise not only improves metabolic health, but also improves immune health in the long run.”