Sarcopenia is an age-related condition characterized by reduced skeletal muscle mass, strength, and physical performance. Sarcopenia is the most important cause of frailty in older adults as it is strongly associated with an increased incidence of falls, impaired mobility, loss of independence, and increased risk of metabolic disorders (i.e. type 2 diabetes). Remaining physically active is critical to maintain muscle mass, however older adults experience more frequent periods of physical inactivity (e.g. due to surgery, hospitalization, acute illness) that result in muscle disuse. Muscle disuse rapidly decreases skeletal muscle mass, and is particularly problematic for older adults due to their pre-existing risk for sarcopenia. Equally concerning is that older adults have an impaired ability to recover lost muscle mass and strength following a period of muscle disuse. Therefore, physical inactivity and muscle disuse represents a "catabolic crisis" for older adults that increases age-related muscle deterioration and accelerates the progression of sarcopenia.
The overall aim of this research is to understand how periods of muscle disuse cause skeletal muscle loss in older adults, and to identify effective ways to prevent it. Skeletal muscle protein metabolism is negatively affected by disuse. Alternatively, healthy nutrition and regular exercise help maintain muscle mass by preserving healthy muscle protein metabolism. This research will apply state-of-the-art methods to measure muscle protein metabolism to determine how muscle mass is lost during a period of disuse and why older muscles have an impaired ability to recover. Subsequently, this research will develop new approaches focused on optimal nutrition and exercise practices for the prevention and rehabilitation of disuse-induced muscle loss. The information from this research will contribute to the development of therapeutic strategies that will ultimately slow the process of sarcopenia, thereby improving the health and well-being of a diverse and expanding population of older adults living in Québec.