Different components of frailty in the aging subjects—The role of sarcopenia

Abstract Frailty is a multisystem impairment that makes an individual vulnerable to external or internal stressors. Sarcopenia, the age-dependent loss of muscle mass and function, is considered as the biological substrate, whereby the consequences of physical frailty develop. Sarcopenia severely impairs the individual quality of life, increasing the occurrence of falls, disability, institutionalization, leading to increased mortality. In this chapter, we focused on sarcopenia as a multifactorial syndrome, discussing the major contributors to its development. We first analyzed the biological mechanisms involved in sarcopenia onset and progression, starting from changes in muscle structure and function and continuing with the role of mitochondrial dysfunction, anabolic resistance, hormonal changes, and inflammation. Also, we analyzed the genetic susceptibility and lifestyle factors (nutrition and physical activity) that may contribute to the disease. Finally, we discussed the management of sarcopenia and the new advancements in treatments, useful to reduce the burden for public health.