When young people think about their muscles, they often focus on enhancing their muscle size and strength for cosmetic or athletic reasons. Those older than 50, however, need to be more concerned with just keeping the muscle they have. On average, people over the age of 50 lose 1 to 2 percent of their muscle mass each year, and after age 60, this number increases to 3 percent. Bed rest, lack of exercise and sedentary behavior in the elderly can speed up this gradual loss over time. Why is maintaining muscle so important for the elderly?
The simplest reason is that muscle is essential for all kinds of movement. Mobility is a crucial component of maintaining independence as we age. Adequate muscle mass and strength allow seniors to continue performing simple daily activities—things like bathing, getting dressed and preparing food—without assistance. Another less obvious reason is that muscle burns a large percentage of the energy that we get from the foods we eat. Losing muscle mass means that we do not use the energy from food as effectively, which can lead to chronic health conditions. In fact, loss of muscle mass is a major contributor to the increased rates of type 2 diabetes in older adults.
Current research has revealed, however, that muscle size is not the only, or even best measure of muscle health. Scientists have traditionally used the term “sarcopenia” to refer to aged-related loss of muscle mass, but many scientists are now focusing more on “dynapenia,” which indicates the loss of muscle function due to aging. New research is showing that how well muscle works can be just as important as how much muscle mass remains. In fact, a person with a smaller amount of muscle mass whose muscle function is good may be stronger and healthier than someone with more muscle mass but poor muscle function. This realization has led to new strategies for promoting muscle health in aging. Although maintaining muscle mass is still important, new approaches are targeting improvement in muscle function. These strategies go beyond simply lifting weights and look at ways to make the inner machinery of the muscle work better. Although nothing can completely stop the loss of muscle function with age, promising new nutritional and exercise therapies are emerging to substantially slow the decline, helping seniors stay active and independent for as long as possible.
Benjamin Miller, PhD, is an associate professor in the department of Health and Exercise Science at Colorado State University. He co-directs the Translational Research in Aging and Chronic Disease (TRACD) Laboratory.