Exercise drives metabolic integration between muscle, adipose and liver metabolism and protects against aging-related diseases

Abstract

Over the last few decades, metabolic disease rates have been on the rise, and this is partially due to older individuals (>65 years of age) making up a higher percentage of the general population. As a result, older age is recognized as a major factor in the global metabolic disorders epidemic (insulin resistance, type 2 diabetes (T2D), fatty liver) and chronic disease conditions (Alzheimer's, cardiovascular disease, etc.). In addition, aging synergizes with obesity and chronic physical inactivity to further drive risk. Exercise or moderate to vigorous physical activity induces adaptations that positively modulate metabolic health in all age groups, including older individuals. Most studies have focused on how aging negatively impacts metabolic function in a specific tissue and how exercise offsets those declines and improves metabolic function. However, during exercise, multiple tissues work in concert to coordinate energy metabolism and maintain metabolic homeostasis. As a result, the metabolic stress of exercise results in long-term adaptations, which are associated with protection against metabolic disease states through mechanisms that are incompletely understood and even less investigated in older individuals (>65 years of age). This review focuses on how exercise affects skeletal muscle, liver, and adipose metabolism in an integrated fashion to modulate improved metabolic health in the context of aging.