What is Muscular Fat?
Muscular fat, also known as intramuscular fat (IMF) or intermuscular adipose tissue (IMAT), refers to the fat deposited within muscle tissue. This is different from subcutaneous fat (fat under the skin) or visceral fat (fat around organs). Intramuscular fat is visible fat located inside the muscle itself.
Several sources describe intramuscular fat's role and implications:
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Muscle Function and Mobility: Studies show a strong correlation between higher intramuscular fat and decreased muscle function and mobility, particularly in older adults and those with various health conditions. (https://pmc.ncbi.nlm.nih.gov/articles/PMC3910392/)
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Muscle Degeneration: In conditions like muscular dystrophy, muscle fibers are progressively replaced by fatty tissue. This replacement contributes to muscle weakness and loss of function. (https://www.ninds.nih.gov/health-information/disorders/muscular-dystrophy, https://www.hopkinsmedicine.org/health/conditions-and-diseases/muscular-dystrophy) Fat infiltration into the muscle is also observed in conditions such as low back pain. (https://www.sciencedirect.com/science/article/pii/S2589004224004425)
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Muscle Mass and Strength: Lower muscle mass often accompanies greater intramuscular fat infiltration, resulting in reduced muscle strength. (https://pubmed.ncbi.nlm.nih.gov/15860469/)
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Misconception about Muscle Turning into Fat: It's crucial to clarify that muscle does not transform into fat when you stop exercising. Muscle and fat are distinct tissues. (https://www.piedmont.org/living-real-change/does-muscle-turn-to-fat-when-you-skip-workouts)
While some intramuscular fat is normal, excessive accumulation can negatively impact health and physical performance. Research continues to explore the complexities of intramuscular fat and its influence on various health outcomes.
