Predictors of physical inactivity in elderly patients with chronic obstructive pulmonary disease

Background Aging may contribute to decreased physical activity in chronic obstructive pulmonary disease (COPD). We explored the predictors of physical inactivity in older patients with COPD.

Methods Thirty male patients with clinically stable COPD participated in the study (age 66.9 ± 4.3 years, forced expiratory volume in 1 second [FEV₁, % of predicted] 52.6 ± 24.6%). Patient characteristics were recorded. Pulmonary function testing was performed and disease stage was determined using the Global Initiative for Chronic Obstructive Pulmonary Disease (GOLD) classification system. Maximal inspiratory and expiratory muscle strength and quadriceps muscle strength were determined using a hand-held device. Dyspnea perception was assessed using the modified Medical Research Council (MMRC) scale. Functional capacity was evaluated using a 6-minute walk test (6MWT). Heart rate and oxygen saturation were recorded before and after 6MWT. Physical activity was assessed using the International Physical Activity Questionnaire (IPAQ).

Results In elderly COPD patients, the IPAQ sitting score was significantly related to 6MWT distance (r = -0.51), GOLD stage (r = 0.52), paroxysmal nocturnal dyspnea (r = -0.42) and orthopnea (r = -0.50), MMRC score (r = 0.40), FEV₁ (r = -0.48), FEV₁/forced vital capacity (FVC) (r = -0.47), forced expiratory flow between 25% and 75% of FVC (r = -0.43), peak expiratory flow (r = -0.43), baseline heart rate (r = 0.40), change in heart rate (r = -0.46), and baseline oxygen saturation (r = -0.43, p < 0.05). GOLD stage, change in heart rate, and orthopnea independently predicted the IPAQ sitting score (R = 0.732, R² = 0.536, F_(1,24) = 4.769, p = 0.039).

Conclusion Disease severity, heart rate response to exercise, and orthopnea are determinants of physical inactivity in elderly COPD.