Sarcopenia is the age-related loss of muscle mass, strength, and endurance. Sarcopenia is the loss of muscle function associated with degeneration of muscle that occurs as we age. But, other factors beside aging contribute to sarcopenia including physical inactivity and declining sex hormone levels especially low testosterone.
Sarcopenia is Greek for “poverty of flesh” just like osteopenia is “poverty of bone”.
Sarcopenia is a growing health concern and is associated with falls, poor balance, diminished gait speed, and disability. And, much of it is preventable. Sarcopenia also greatly diminishes quality of life.
Sarcopenia and Muscle Physiology
We have two main type of muscle fibers (there’s actually more than 2 types of fibers, but we’re going to keep it simple); type 1 and type 2. Type 1 fibers are endurance fibers and type 2 are strength and power fibers. There is a loss of both type 1 and type 2 fibers with sarcopenia, but the size or circumference of type 2 fibers also declines in sarcopenia. This explains why muscles become smaller as we age and why many individuals struggle more with strength and power activities (getting out of a chair or climbing stairs) to a greater degree than endurance activities like walking.
Sarcopenia is associated with a loss of satellite cells. Satellite cells are activated during exercise or when muscle has been injured. Satellite cells help repair muscle fibers. The ability to repair and rebuild muscle is diminished in sarcopenia because of declining satellite cells. Muscle fibers are then replaced with fat and scar tissue.
Most of the time the diagnosis of sarcopenia can be made by simple observation. To monitor treatment and for research studies DEXA scanning is used and can accurately measure lean muscle mass which can then be followed to monitor the response to treatment.
Prevention and Treatment of Sarcopenia
Sarcopenia is better prevented than treated. Exercise, nutrition, and hormone optimization form the cornerstones for both prevention and treatment. Resistance training is essential to limit the decline in type 2 muscle fibers. Muscle is made of protein. Therefore, adequate protein must be present in the diet. Protein intake for many is poor to begin with and probably even more inadequate in the elderly. I tell many of my elderly patients to consume protein shakes not only to protect muscle, but to provide the building blocks for hormone and neurotransmitter production. Omega-3 fatty acids and creatine have been shown to improve muscle strength, too.
Hormone Optimization and Sarcopenia
At some point, though, exercise and nutrition will not be enough for most individuals to prevent sarcopenia. Sarcopenia is going to occur unless hormone levels are optimized. For muscle this means testosterone, DHEA, and possibly growth hormone need to be optimized. This is true for men and women. We can create a demand for these hormones through strength training and high intensity interval training. However, the body’s ability to produce these hormones in response to these stimuli diminishes as we age. So help is frequently needed in the form of hormone replacement.
In my opinion we need to be more aggressive treating men and women for sarcopenia. Yet, there remains a reluctance in the medical community to address this growing problem of sarcopenia. It is simply dismissed as “a part of aging”. Well it is, but it but should not be ignored. Too much money is being spent because too many elderly have too little strength to care for themselves and perform the basic daily activities.
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