
Why Does This Happen?
When your muscles aren’t being used or suffer damage, your body has a surprising way of adapting—by filling in the gaps with fat cells. Over time, this process weakens your muscles, leading to a noticeable drop in strength and functionality. It’s a stark reminder of the importance of staying active and taking care of your muscle health!
Causes of Fatty Infiltration:
Aging:
As individuals age, muscle mass naturally declines, while fat deposition within muscles increases. Hormonal shifts, including declines in testosterone and estrogen, exacerbate this process.
Physical Inactivity:
Sedentary lifestyles or prolonged periods of muscle disuse promote fat infiltration.
Obesity and Altered Energy Regulation:
Excess body fat and disruptions in hormones like leptin contribute to ectopic fat deposition in muscles.
Neuromuscular Disorders:
Conditions such as muscular dystrophy, nerve injuries, and prolonged inflammation impair muscle function, leading to fat infiltration.
Medications and Hormonal Factors:
Glucocorticoid treatments are linked to higher levels of intramuscular fat, compounding the risk
Chronic Systemic Inflammation:
Persistent inflammation, common in aging and metabolic diseases, accelerates fat accumulation within muscles.
Why Fatty Infiltration Is Detrimental:
Decreased Muscle Quality and Strength:
Fat deposition reduces muscle density and contraction efficiency, leading to weaker and less functional muscles.
Muscle performance and mobility are significantly impaired.
Metabolic Dysfunction:
Intramuscular fat disrupts glucose metabolism, contributing to insulin resistance and increasing the risk of type 2 diabetes and metabolic syndrome.
Increased Risk of Injury and Atrophy:
Fatty infiltration contributes to muscle degeneration, raising the likelihood of injuries and exacerbating muscle loss over time.
Higher Mortality Risk:
Studies link elevated muscle fat levels with increased mortality, particularly in older adults.
Health Interventions:
Strategies to counteract fatty infiltration (Myosteatosis) include regular physical activity, resistance training, maintaining healthy body composition, and addressing hormonal or metabolic imbalances through targeted therapies.
REFERENCES:
Hamrick, M. W., McGee-Lawrence, M. E., & Frechette, D. M. (2016). Fatty Infiltration of Skeletal Muscle: Mechanisms and Comparisons with Bone Marrow Adiposity. Frontiers in Endocrinology, 7. https://doi.org/10.3389/fendo.2016.00069
Marcus, R. L., Addison, O., Kidde, J. P., Dibble, L. E., & Lastayo, P. C. (2010). Skeletal muscle fat infiltration: Impact of age, inactivity, and exercise. The Journal of Nutrition, Health & Aging, 14(5), 362–366. https://doi.org/10.1007/s12603-010-0081-2
Miljkovic, I., Kuipers, A. L., Cauley, J. A., Prasad, T., Lee, C. G., Ensrud, K. E., Cawthon, P. M., Hoffman, A. R., Dam, T.-T., Gordon, C. L., & Zmuda, J. M. (2015). Greater Skeletal Muscle Fat Infiltration Is Associated With Higher All-Cause and Cardiovascular Mortality in Older Men. The Journals of Gerontology: Series A, 70(9), 1133–1140. https://doi.org/10.1093/gerona/glv027
Outreach, R. (2022, December 6). Co-existence of hepatosteatosis and skeletal muscle fat infiltration. Research Outreach. https://researchoutreach.org/articles/co-existence-hepatosteatosis-skeletal-muscle-fat-infiltration/
Zhu, Y., Hu, Y., Pan, Y., Li, M., Niu, Y., Zhang, T., Sun, H., Zhou, S., Liu, M., Zhang, Y., Wu, C., Ma, Y., Guo, Y., & Wang, L. (2024). Fatty infiltration in the musculoskeletal system: pathological mechanisms and clinical implications. Frontiers in Endocrinology, 15. https://doi.org/10.3389/fendo.2024.1406046
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