The IL-6 Enigma: Highlighting the Complex Relationship between Exercise and Health [Synopsis]
Synopsis of The IL-6 Enigma: Highlighting the Complex Relationship between Exercise and Health. For scientific argument and references refer to full article.
Introduction
Recent advancements challenge the traditional view of muscles as mere mechanical entities, revealing their crucial role in signalling through myokines—molecules released during muscle contraction. This newfound understanding underscores the significant influence of exercise on health, particularly through its impact on inflammation and disease pathways. The interplay between exercise and disease prevention encompasses cancer, autoimmune diseases, obesity, and mental disorders, revealing interconnected mechanisms across various conditions.
The IL-6 Paradox
Interleukin-6 (IL-6) is a critical protein in immune regulation with a dual role in disease prevention and promotion. It serves as a marker for chronic inflammation and the severity of diseases like COVID-19, autoimmune conditions, and heart diseases. Elevated IL-6 levels can either protect against or contribute to cancer, depending on its context—acting as a pro-inflammatory cytokine (cIL-6) in disease and an anti-inflammatory myokine (mIL-6) during exercise. This paradox highlights the complexity of IL-6's role in health and disease.
Anti-Inflammatory Effect of Exercise
Exercise-induced IL-6 can have anti-inflammatory effects, particularly in fit and/or well-conditioned individuals, reducing overall inflammation levels. Conversely, unconditioned individuals or those who are overweight (specifically with higher levels of body fat) may experience increased inflammation and cancer risk due to muscle microtrauma and elevated IL-6 levels which is likely to result from physical activity. This is because activated muscles, typically through exercise and general activity, are identified by the immune system in a manner similar to infection, injury, or sepsis, which is the basis of autoimmune disorders. Proper exercise without inducing muscle damage can promote beneficial IL-6 myokine production, enhancing insulin sensitivity and reducing chronic inflammation.
The Complex Role of Regulatory T-Cells
Regulatory T-cells (Tregs) play a protective role against exercise-induced inflammation. Regular exercise promotes Treg proliferation, which helps mitigate inflammation and bolsters the body's defences. However, unconditioned individuals may lack this protective mechanism, emphasizing the importance of consistent exercise for developing adequate immune responses.
The Adiposity Connection
High adiposity is linked to low-grade inflammation, increasing cancer and general disease risk and hindering effective inflammation regulation. The failure of myokine activation in obese individuals impairs their ability to manage inflammation, contributing in particular to both obesity and cancer. Exercise-induced physiological changes can counteract this, suggesting tailored exercise interventions for inflammation control and chronic disease prevention.
Obesity, while increasing chronic disease risk, also enhances recovery due to the greater muscle load during activity. Individuals with excess adiposity generally have increased musculature to support the additional weight. Consequently, lean muscle mass, rather than BMI or body-fat percentage, is a better health indicator. This paradox underscores the importance of muscles in health. Effective muscle function and exercise can reduce inflammation, improve chemotherapy outcomes, and enhance overall health, benefiting those with cancer and chronic disease conditions.
Conclusion
Understanding myokines, particularly IL-6, and their role in health highlights the complex relationship between exercise and disease prevention. Tailored exercise strategies promoting beneficial IL-6 myokine production can reduce inflammation, enhance treatment efficacy, and improve overall fitness. Further research into Tregs and mitochondrial oxidative capacity during exercise will deepen our understanding of these mechanisms and their implications for health and disease management.
