Obesity and sedentary lifestyles put people at greater risk of developing a familiar list of health conditions, including type 2 diabetes, high blood pressure, high cholesterol, and cardiovascular disease. But for older adults, the list includes another, lesser-known condition: sarcopenia.
Sarcopenia is a loss of muscle mass, strength, and function associated with aging. It is thought to be a major component of the frailty syndrome that puts older adults at risk for falls, impaired healing after trauma or surgery, and other adverse health outcomes.
Inflammation may lead to sarcopenia
While studies have shown correlations between sarcopenia and obesity and sedentary behaviors, very little is known about what actually causes sarcopenia. Among the researchers working to change that is Kyle Timmerman, an associate professor in Miami University’s Department of Kinesiology and Health.
Timmerman was recently awarded over $430,000 by the National Institute on Aging, part of the National Institutes of Health (NIH), to explore the role chronic low grade inflammation might play in the development of sarcopenia in obese and sedentary adults age 55 and older.
“The body’s ability to generate a short-term increase in inflammation is a critical component of immune function and wound healing,” Timmerman says, “but as we age, baseline levels of inflammation start to creep up, especially if we gain weight and are less physically active.”
Timmerman believes chronic low-grade inflammation may interfere with signals that tell the body to create the proteins that form muscles. Normally, he says, eating or exercising acts as a “switch” that turns on muscle protein synthesis in our bodies. But as we age and inflammation increases, our bodies don’t always seem to get the message that we’ve eaten or exercised, so muscle protein synthesis doesn’t get turned like it did when we were younger.
Weight loss and exercise could help
Although it may not be possible to completely eliminate age-related inflammation, Timmerman thinks weight loss and exercise might help reduce it in obese, sedentary seniors. As part of the NIH-funded study, he will test his theory using volunteers who are at least 55 years old, are relatively inactive, and have body mass indexes (BMIs) of 27 or higher. Each volunteer will be assigned to one of four groups:
• Diet-induced weight loss – Participants in this group will receive nutritional counseling designed to help them lose between 5% and 10% of their body weight over a six-month period.
• Aerobic exercise – Participants in this group will be coached in an exercise training program. The goal, after a period of conditioning, is for participants to meet American College of Sports Medicine guidelines, which call for vigorous intensity aerobic exercise three days per week.
• Diet-induced weight loss + aerobic exercise – Participants in this group will receive both the nutritional counseling and exercise training described above.
• Control – Participants in this group will not receive any nutritional counseling or exercise training.
To determine what effect weight loss and/or exercise has on inflammation, Timmerman will measure levels of the protein he suspects to be responsible for the impaired signaling for muscle protein synthesis, TNF alpha converting enzyme
(TACE). Any reduction of TACE levels in the intervention groups, as compared with the control group, will suggest that weight loss and/or exercise do effectively reduce chronic low-grade inflammation in older adults. They will also determine if reductions in inflammation are associated with an improved ability of nutrient intake to “flip the switch” that activates muscle protein synthesis.
“That will allow us to see what interventions help minimize the loss of muscle mass and function in older adults, and then help us better understand the mechanisms that underlie the development of sarcopenia,” Timmerman says.
Student involvement is a win-win
Timmerman and his co-investigator and departmental colleague, Beth Miller, will involve a number of graduate and undergraduate students in their research. Timmerman’s students will help implement the exercise assessment and training, while Miller’s will assist with dietary assessment and counseling.
Having students involved in the project is a win-win, Timmerman says. The students – many of whom aspire to careers in dietetics, physical therapy, and other health professions – benefit from the hands-on experience working with real people who are similar to the patients they will encounter as professionals. In turn, the students improve the quality of the research, not only by taking on some of the workload, but also by encouraging volunteers to stick with the study.
Virtually every research study experiences volunteer attrition. Sometimes the reasons can’t be helped: a participant might move or develop a health condition that makes them ineligible to continue in the study. But because any loss of participants affects the integrity of the data being collected, researchers work hard to avoid preventable reasons for dropping out of a study, such as a participant’s losing interest or becoming overwhelmed by a study’s requirements. That’s where Timmerman says student involvement is invaluable.
“Having worked with older adults before, I know they love working with college students,” says Timmerman. “It really helps them stick with the program. I’ve been part of exercise training studies before where we just said, ‘Hey, show up,’ and there wasn’t much of a community feel, so a lot of people ended up dropping out.”
In the end, keeping people engaged is an overarching theme of Timmerman’s work. As a researcher, he seeks to keep older adults healthy and active so they can continue contributing to their communities. As a teacher and research mentor, he helps strengthen communities of research and professional practice by inspiring and shaping the next generation of members.
Written by Heather Beattey Johnston, Associate Director of Research Communications, Office for the Advancement of Research and Scholarship, Miami University.
Weight check photo by Senior Airman John Gordinier via U.S. Air Force. Walk in the park photo via Max Pexel. Both used under public domain.