Muscle Loss: Aging Begins at 30: Virtual Hospital

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Aging Begins at 30

Muscle Loss

Ian Maclean Smith, M.D.
Emeritus Professor
Department of Internal Medicine
University of Iowa Hospitals and Clinics
Creation Date: September 2001
Last Revision Date: September 2001
Peer Review Status: Internally Peer Reviewed

It's a fairly new word on the geriatric frontier, perhaps five years old. Welcome to sarcopenia. It means lack of flesh or muscle. In contrast, loss of flesh and obvious chronic illness is called cachexia. Like many other tissues, such as bone, even when you are healthy you start losing muscle around age 30. Remember "Aging Begins At 30." Despite regular exercise, loss of muscles marches on with advancing age. This may lead to loss of strength and function and eventually loss of independence. Muscle wasting in the legs can lead to falls, and thinning bones break. You don't detect it because fat fills in the gap. Frailty in the very old is often related to loss of muscle.

Such damage can to some extent be prevented or reversed by regular exercise. The ability to climb stairs can be improved 25% by exercise.

Loss of muscle increases six-fold at the time of the menopause so it may have a connection with estrogen. Is the problem in the muscle or do chemical cell messengers direct it from afar? One such messenger might be insulin-like growth factor. When normal muscle is damaged, muscle repair cells are summoned from the edge of the muscle. With older muscle this is less efficient than in younger muscle. If the nerve to a muscle dies, a neighboring nerve can double its load, but that's about its limit. Muscle is a great store of useable protein, which may be needed quickly to combat an infection. When muscle falls to 60% of baseline these functions of the body no longer work.

I remember Sarah, a former patient of mine aged about 85, who gradually was getting thinner and thinner with associate muscle weakness. Suddenly one day she showed up at church with her son, daughter-in-law and granddaughter much more sprightly. Had the nursing home got her on an exercise program? You can do it yourself by climbing stairs and slowly increasing the number. I work out once a week for about 45 minutes but it would be better if it was twice a week.

When you have a name for a phenomenon interest perks up. A recent study from Tufts University in Boston shows that muscle protein production is slightly higher in healthy elderly men (average age 70) than in similar build young men (average age 28). They used radioisotopes and muscle biopsies to do a very careful study (JAMA 9-12-01). Muscle loss is not due to reduced protein turnover. We have to look elsewhere.

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See related Patient Topics Bones, Joints and Muscles or Muscle Disorders.

See related Provider Topics Bones, Joints and Muscles or Muscle Disorders.

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