Physical inactivity in COPD: a key determinant of frailty and adverse outcomes.

Physical inactivity is a determinant feature in chronic obstructive pulmonary disease (COPD) and is strongly associated with adverse clinical outcomes, including exacerbations, hospitalizations, and mortality. Increasing evidence suggests that inactivity is not merely a consequence of respiratory impairment but may actively contribute to disease progression and the development of frailty. This review examines the mechanisms underlying physical inactivity in COPD, its clinical implications, and current strategies for its assessment and management. Physical inactivity arises from a complex interplay between ventilatory limitation, skeletal muscle dysfunction, systemic inflammation, and behavioral factors, and it often develops early in the disease course, independently of airflow limitation. Recent studies have identified distinct inactivity phenotypes and highlighted the importance of total daily movement, including light-intensity activity. Importantly, physical inactivity plays a central role in the transition toward sarcopenia and frailty, contributing to a reduced physiological reserve and an increased vulnerability to adverse outcomes. Although interventions such as pulmonary rehabilitation and activity coaching can improve exercise capacity and short-term activity levels, their long-term effectiveness remains limited. These findings highlight the need for novel earlier, personalized, and multimodal approaches. Targeting physical inactivity represents a promising strategy to modify disease trajectory and improve long-term outcomes in patients with COPD.