THE LARGEST ENDOCRINE ORGAN IN THE BODY
Understanding the complex balance between anabolic & catabolic factors, and how they exacerbate the severity and speed of aging, will be crucial in determining how to best prevent or reverse the effects of Sarcopenia. As human skeletal muscle will secrete a variety of compounds in response to muscular contractions; which are involved in the inflammatory response, sedentary behaviors will support inflammation and an associated 'suppression' of the muscle derived anti-inflammatory response.
Researchers have estimated that the prevalence of Sarcopenia may be as high as 30% > 60 years of age, and 50% > 80 years of age. We've also identified the most important endocrine myokines secreted by muscle as being; IL-6, IL-8, IL-15, Brain Derived Neurotrophic Factor (BDNF) and Leukemia Inhibiting Factor (LIF)
As the accumulation of fat tissue will encourage further inactivity, this will in turn support a chronic inflammatory state within the body; which is known to be involved in the generation of a variety of chronic disease states, from insulin resistance, to neurodegenerative disease, to cancer.
Science: 2. Physical activity...low-level inflammation.
Science: 3. The anti-inflammatory effect of exercise.
Let's zero-in on Interleukin-6, as it appears to be one of the more important muscle derived anti-inflammatory factors released by muscular contractions. In laboratory studies, mice who are deficient in IL-6 demonstrate high blood sugar & eventually develop mature onset obesity, suggesting that IL-6 is involved in blood sugar homeostasis. IL-6 released via muscular contractions may will help prevent insulin spikes and keep those levels balanced.
As listed above, some of the other factors related to Sarcopenia/chronic disease prevention - such as IL-15 - will contribute to muscle growth & fat oxidation - specifically visceral fat.
Furthermore, BDNF will contribute to the survival & growth of neurons in the brain, and also contribute to the prevention of Alzheimers, Major Depressive Disorder, acute coronary syndromes, and T2 diabetes. BDNF will also activate an enzyme which leads to the oxidation of fat. The authors conclude that the aging body may be strongly influenced by the balance of chronic sedentary low level systemic inflammation; see FIGURE 2, and the anti-inflammatory effects of muscular contractions; see FIGURE 1.
It's my hope that a continuation of this type of research in the near future will continue to reveal and provide support to the positive effects that exercise might have on the prevention of a whole host of chronic, and previously thought intractable diseases.