Aging in muscle

Abstract

Skeletal muscle aging is the primary factor limiting the scope of human activities and quality of life. Aging of cardiac muscle impairs delivery of oxygen and substrates to the energy-demanding organs of the body affecting their function. Thus, both the muscles taken together largely determine the pace of aging in an individual. With improvement in medical system, the life expectancy has increased dramatically in the last century, which has resulted in a huge increase in the number of those considered aged. In recent decades, the number of people with metabolic disorders, including type 2 diabetes, hypertension, and hyperlipidemia, has been increasing steadily. Diabetes and hyperlipidemia are very closely intertwined with muscle aging, which in turn speeds up the clinical manifestation of the disorders. Muscle protein synthesis, mitochondrial biogenesis, and adenosine triphosphate (ATP) production are significantly affected by both aging and metabolic disorders. During aging, levels of anabolic hormones, such as testosterone, growth hormone, and insulin-like growth factor (IGF)-1 decrease and that of catabolic agents like interleukin 6 (IL-6) increases, contributing to muscle wasting among the elderly individuals. Incorporation of increased physical activity (including exercise) in routine life has been demonstrated to reduce the pace of aging, thereby promoting healthy aging.