Ali Abdul-Sater
The research, done on a mouse model, found that moderate exercise changes function of macrophage cells - white blood cells responsible for killing off infections, healing injury and otherwise acting as first responders in the body - in bone marrow.
"Much like if you train your muscles through exercise, we showed that exercise of moderate intensity ended up training the precursors of those macrophages in the bone marrow," says Abdul-Sater. "The way that exercise is doing this is by changing the way those cells breathe, essentially, how they use oxygen to generate energy and then changing the way they access their DNA."
While many studies look at temporary boosts to the immune system immediately after exercise, this study, published in the journal AJP-Cell, found these changes occurred even a week later, suggesting that the changes were long term.
Inflammation in the body is sometimes positioned in the context of its negative effects, but inflammation is the body's response to infection and other stressors, and some level of inflammation is necessary and desirable.
"Inflammation is amazing, it's a very important part of our normal immune response," says Abdul-Sater. "What we're concerned about is excessive inflammation. Heart disease, diabetes, many cancers and autoimmune diseases, all essentially begin because there was an inappropriate inflammatory response."
Abdul-Sater found that 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 access DNA. So all that just takes time."
Abdul-Sater says that because the inflammatory response is a very ancient one, this aspect of the immune system is generally very similar across mammals, and he expects the research would translate well to humans. In the next phase, Abdul-Sater and collaborators from the university will collect immune cells from human volunteers who will do exercises of various intensities to see which workout routines are most beneficial to balance the inflammatory response. They will also look at inflammation in mice in more complex infectious diseases similar to COVID-19 and autoimmune disease, where overactive inflammatory responses lead to poor outcomes.
"People that got seriously ill from COVID-19 went into what is called a cytokine storm, essentially, they released this massive number of cytokines, those mediators that are produced by inflammatory cells, which then cause that accumulation of fluid in lungs."
While the findings that exercise is beneficial will not come as a surprise, Abdul-Sater says he hopes that by finding the underlying mechanisms of the beneficial impact, this knowledge can be put to good use.
"The thing with humans is there's no intervention that will work on everyone. We know that, but what this study suggests is that moderate and persistent exercise not only improves metabolic health, but also will improve immune health in the long run."
This story was originally featured in YFile, York University's community newsletter.
