MADISON, Wis. — The gradual loss of muscle mass as people age may be linked to changes in metabolism and the body’s ability to generate and process energy.
That’s according to a University of Wisconsin School of Medicine and Public Health study, which shows these changes occur a lot earlier than previously thought, before the muscles show outward signs of aging. The findings were published in the August issue of the journal Aging Cell.
The research involved adult rhesus monkeys in three age groups: younger (corresponding to early 20s for humans), middle-aged (middle 40s) and older (65 years and older). Samples of their quadriceps muscles were analyzed to check for development of the condition, known as sarcopenia.
Using multi-photon laser scanning microscopy at the University of Wisconsin Laboratory for Optical and Computational Imaging, the research team was able to “look” at metabolism in individual cells.
While sarcopenia had already occurred in the older monkeys and there were no signs of the condition in the younger group, lead author Dr. Rozalyn Anderson said there were significant metabolic changes in the middle-aged monkeys that occurred before the start of sarcopenia.
“Their muscles were still big, the animals were still vigorous, and there were no signs of aging,” Anderson, assistant professor of medicine, said. “But, the way they generated and processed energy completely changed. The cells in the middle-aged monkeys were vulnerable in a different way.”
In people, the signs of sarcopenia usually begin in the late 40s and early 50s and lead to an average 3 to 5 percent loss of muscle mass per decade.
Anderson said while the seeds for sarcopenia are sown early, delaying the energetic shift through exercise could significantly slow the pace of muscle mass loss.
“The muscles should be kept metabolically active to reduce the effects of sarcopenia,” she said. “By keeping your muscles energized, you are keeping a key part of energy balance in your body. As we age, it gets more difficult to keep that metabolism tightly connected, which eventually leads to muscle shrinkage. That’s a problem because muscles are a huge part of body balance.
“People know about the benefits of exercise, but many don’t do it,” Anderson added. “Yet, there is one thing that is unequivocally known to slow down the effects of sarcopenia, and that’s exercise.”
From the Aug. 14-20, 2013, issue