Lower-Limb Muscle Impairments in Patients with COPD: An Overview of the Past Decade

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disease characterized by airflow limitation. Apart from airflow limitation, patients with COPD may also suffer from extra-pulmonary features such as lower limb muscle dysfunction that contribute to an impaired health status. Since the latest statement on lower-limb muscle dysfunction in COPD in 2014, substantial new evidence has emerged with regard to molecular, cellular, and functional mechanisms underlying muscle plasticity. Therefore, this review aims to provide an updated overview of molecular, cellular, and functional mechanisms of lower-limb muscle plasticity in COPD, integrating evidence that has emerged since the 2014 statement on lower limb muscle dysfunction. Additionally, the effects of exercise training on mechanisms of limb muscle dysfunction are explained. From the evidence of the last decade, it can be concluded that limb muscle dysfunction is a multifactorial process driven by both intrinsic alterations and impairments to the muscle as well as extra-pulmonary influences, thereby reinforcing the need for integrated therapeutic strategies.