Maintaining healthy muscle mass throughout life is not just about physical strength—it has profound implications for your immune system. Dr. Craig Wright, a senior lecturer at the Institute for Physical Activity and Nutrition (IPAN) at Deakin University, emphasizes that muscle mass is a vital reserve of amino acids that support the immune system in fighting off diseases and infections. Recent research highlights the connection between muscle loss and a weakened immune response, increasing the risk of infections.
The symbiotic relationship between muscles and the immune system
Your muscles and immune system work hand in hand: muscles enhance immune function, while the immune system supports muscle growth and recovery. When your muscles are under stress—whether from exercise or injury—immune cells respond quickly to remove waste and initiate healing and regeneration processes.
A study published in PeerJ underscores the importance of macrophages (a type of immune cell) in muscle recovery. These cells first trigger an inflammatory response to eliminate damaged cells and pathogens. They then shift roles to suppress inflammation, releasing growth factors that stimulate tissue repair and growth. This dual role is key to ensuring muscles recover effectively, growing stronger and more resilient.
The role of myokines in muscle health
When muscles contract during exercise, they release proteins called myokines. These proteins act as chemical messengers, influencing various bodily functions, including immune regulation.
A study published in Endocrine Reviews reveals that skeletal muscles function as endocrine organs, producing and releasing hundreds of myokines. These myokines affect muscles locally (autocrine), in adjacent tissues (paracrine), or throughout the body (endocrine).
Recent studies show that exercise-induced myokines facilitate communication between muscles and other organs, such as fat tissue, blood vessels, bones, the brain, intestines, liver, pancreas, and skin. Although only a few myokines have been linked to specific functions in humans, they are known to influence bone formation, cognition, fat browning, metabolism, muscle growth, skin health, and even tumor development.
This suggests that myokines could serve as valuable biomarkers for adjusting exercise programs, especially for individuals suffering from conditions like cancer, diabetes, or neurodegenerative diseases.
Muscle’s role in glutamine production
Glutamine is the most abundant non-essential amino acid in your body and plays a crucial role in both immune function and muscle health.
Muscles produce glutamine by breaking down branched-chain amino acids (BCAAs) and releasing it into the bloodstream. According to a study in Nutrients, skeletal muscles store approximately 80% of the body’s glutamine, with concentrations in muscle tissue being 30 times higher than in the blood. This highlights the vital role muscles play in maintaining glutamine levels.
Glutamine is essential for immune activities, including the growth of lymphocytes (white blood cells), the production of cytokines (chemical messengers), and maintaining the function of macrophages and neutrophils (cells that fight infections).
While the body regulates glutamine through various organs—such as the intestines, liver, and muscles—during illness or physical stress, glutamine becomes a critical nutrient, and its availability may be compromised due to disruptions in the body’s amino acid balance.
Muscle mass boosts circulation and immune function
Muscle mass is vital for a robust immune system because it enhances circulation. When muscles contract during exercise, they help move blood and lymph throughout the body. This movement is crucial for effective immune function, as it ensures that immune cells are efficiently transported to where they are needed.
The lymphatic system, responsible for removing toxins and waste, relies on muscle contractions to propel lymph fluid, unlike the cardiovascular system, which uses the heart as a pump. Regular muscle engagement improves this fluid movement, enhancing the efficiency of the immune system.
Muscle activity reduces chronic inflammation
Chronic inflammation can compromise immune health and lead to a range of health issues, including autoimmune diseases and other long-term conditions. Regular physical activity stimulates muscle contractions that release powerful myokines, such as interleukin-10 (IL-10) and interleukin-37 (IL-37), which help regulate inflammatory processes in the body.
Research published in Science Immunology found that exercise activates T regulatory cells (Tregs). These cells are essential for reducing inflammation caused by exercise, improving muscle function, and increasing overall endurance.
Tregs help minimize muscle damage by reducing interferon levels, a protein associated with aging, inflammatory diseases, and chronic inflammation. By lowering chronic inflammation, muscle activity prevents unnecessary inflammation, supporting a more efficient immune response.
Tips for building and maintaining muscle at any age
To increase or maintain muscle mass and improve immune function, consider these lifestyle changes:
Stay active
As you age, your body’s composition changes, and muscle loss becomes more pronounced. This typically occurs when you stop engaging in activities that promote physical fitness and strength. Rather than using age as an excuse, continue to push your limits. For older individuals, incorporating balance exercises into your routine can help you remain functionally strong and reduce the risk of falls.
Avoid extreme diets
Maintaining muscle mass is crucial for sustaining a high metabolism, which helps you burn more calories at rest and stay lean. As you age, your body becomes less efficient at using protein, making it harder to build and maintain muscle. Extreme caloric deficits are counterproductive.
While drastically cutting calories may seem necessary for weight loss, this approach often leads to muscle loss, which can negatively impact your body composition and slow your metabolism. Adopt a balanced approach by focusing on macronutrient intake and creating only a small caloric deficit. This strategy helps preserve muscle while losing fat.
Increase protein intake
As you age, you become less efficient at using protein to build muscle. It’s crucial to rely on a nutrient-dense diet rich in protein, spreading your intake throughout the day. The recommended protein intake increases with age, ranging from 1.0 to 1.6 grams per kilogram of body weight, with protein ideally spread across 3-4 meals per day.
Lift weights
Building muscle mass doesn’t necessarily mean lifting heavy weights. If you don’t have access to a gym, try any form of resistance training, such as resistance bands or bodyweight exercises (e.g., squats, push-ups).
Prioritize recovery
When engaging in physical activity, it’s essential to allow your muscles time to recover. Training with periodization helps muscles grow and enables the body to use energy during rest to rebuild muscle fibers.
Conclusion
While many people think muscle mass is important only for physical strength, its impact on health is far more significant. Muscles are not just an energy store—they play a critical role in immune function and overall health. With the right exercises, nutrition, and recovery strategies, you can increase muscle mass and ensure a strong immune system.
