The Association between Sleep Quality and Functional Capacity of the Patients with Chronic Obstructive Pulmonary Disease in the National Hospital for Respiratory Diseases, Welisara and Central Chest Clinic, Medical Research Institute, Sri Lanka

Abstract

Background: Sleep disturbances are common in patients with Chronic Obstructive Pulmonary Disease (COPD) and may impact functional exercise capacity. However, the relationship between sleep quality and functional exercise capacity of the patients with COPD in Sri Lanka remains underexplored. Objective: To evaluate the relationship between sleep quality and functional exercise capacity in clinically stable COPD patients Methods: A descriptive cross-sectional study was conducted at the National Hospital for Respiratory Diseases, Welisara, and Central Chest Clinic, Medical Research Institute, Sri Lanka, including a total of 160 clinically stable COPD patients aged 30 to 79 years. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI), categorizing participants into good sleep (PSQI≤5), poor sleep quality (5<PSQI≤11), and severe sleep disturbances (11<PSQI≤21). Functional exercise capacity was measured using the 6-Minute Walk Distance (6MWD) and dyspnea levels were assessed using the Modified Medical Research Council Dyspnea scale. COPD severity was classified according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines. Results: This study included 116 male and 44 female COPD patients with a mean±SD age of 66.43±7.7 years. The majority of patients experienced poor (48.1%) or severe (46.3%) sleep disturbances, with only 5.6% reporting good sleep quality. The 6MWD was significantly differed across sleep quality groups (p<0.001), with poorer sleep quality associated with reduced functional capacity. A strong negative correlation was observed between PSQI global score and 6MWD (p< 0.001), indicating that worse sleep quality was linked to lower functional exercise capacity. Conclusion: The findings highlight a significant association between poor sleep quality and reduced functional exercise capacity observed across older adult COPD patients. The need for targeted interventions to improve sleep and physical function in COPD management is highly recommended.