Moderate Exercise Reduces Inflammation at the Cellular Level, New Study Finds

Inflammation happens when the body’s immune system has a reaction. This could be to pathogens such as germs, foreign bodies, and anything else the immune system recognizes as foreign.

While it can be crucial for restoring tissue and healing, excessive and chronic inflammation can result in conditions such as cancer, diabetes, and neurodegenerative disease.

Studies have shown that exercise can modulate the immune system. Research shows that moderate-intensity exercise exerts anti-inflammatory effects. Various mechanisms have been proposed to explain how exercise exerts these effects, including decreased fat mass and altered function of immune cells known as macrophages.

How exactly exercise induces these changes that reduce inflammation, however, remains unknown. Further research on how this happens could inform treatment and prevention options for inflammation-related health conditions.

Recently, researchers explored how macrophages present in bone marrow changed following exercise to induce anti-inflammatory effects.

They found that regular moderate exercise reduces the inflammatory response by rewiring metabolic and epigenetic function in macrophages.

For the study, the researchers gathered female mice and split them into two groups: one that exercised on a treadmill for one hour per day, and the other that did not exercise at all. Both exercise regimes lasted for eight weeks.

The researchers collected bone marrow-derived macrophages (BMDMs) from both groups of mice and conducted various tests to assess their inflammatory and antiviral responses.

Ultimately, they found that gene expression of inflammatory genes in exercised mice’s BMDM’s was significantly lower than that in sedentary controls, due to changes in the accessibility of those genes for transcription.

The researchers also noted that exercise inhibited other pathways linked to inflammation compared to controls.

To understand why this may be the case, the researchers examined the effects of exercise on mitochondrial function in the BMDMs. Mitochondria play a significant role in metabolic processes that control inflammation and macrophage activation.

They found that moderate exercise reduced oxidative stress in BMDMs, and improved overall mitochondrial quality in BMDMs. These improvements, they noted, occurred similarly to how mitochondria adapt in muscle cells following exercise.

The researchers next wanted to see whether these effects could be maintained long-term. To do so, they examined BMDM’s from exercised mice after they stopped exercised. After exercise was stopped for two weeks, both oxidative stress and mitochondrial potential reduced to sedentary levels.

Sources:

Kawanishi N, Yano H, Yokogawa Y, Suzuki K. Exercise training inhibits inflammation in adipose tissue via both suppression of macrophage infiltration and acceleration of phenotypic switching from M1 to M2 macrophages in high-fat-diet-induced obese mice. Exerc Immunol Rev. 2010;16:105-18. PMID: 20839495.

Nieman DC, Pence BD. Exercise immunology: Future directions. J Sport Health Sci. 2020 Sep;9(5):432-445. doi: 10.1016/j.jshs.2019.12.003. Epub 2019 Dec 30. PMID: 32928447; PMCID: PMC7498623.

W.  Petersen, A. M., & Pedersen, B. K. (2005). The anti-inflammatory effect of exercise. Journal of Applied Physiology. https://doi.org/A0164-4

Barcellos, L. A., Gonçalves, W. A., Paulo, M., Guimarães, J. B., Martins, C., Resende, C. B., Russo, R. C., Coimbra, C. C., Silva, A. N., Teixeira, M. M., Rezende, B. M., & Pinho, V. (2021). Effect of Physical Training on Exercise-Induced Inflammation and Performance in Mice. Frontiers in Cell and Developmental Biology, 9, 625680. https://doi.org/10.3389/fcell.2021.625680

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