Influence of basal physical activity and air quality on a walking programme in patients with COPD

Promoting physical activity is essential in chronic obstructive pulmonary disease (COPD) management, but the role of air quality in urban walking programmes remains unclear. This study assessed baseline factors and the impact of air quality on the success of a COPD walking programme.

In this prospective observational study, 72 patients with COPD and peripheral oxygen saturation (SpO_₂) ≥94%, were recruited from a university hospital. Baseline clinical data, functional tests, physical activity (steps/day) and sedentary status (Yale Physical Activity Survey (YPAS)) were collected. Patients participated in a 3-month walking programme, with self-documented physical activity tracked using pedometers and daily Air Quality Index (AQI) monitoring from a central site. Responders were defined as those with an increase of >600 steps/day. Baseline characteristics and AQI were compared between responders and non-responders, and multivariate logistic regression identified predictors of success.

42 patients (58%) achieved programme goals. The mean COPD Assessment Test score and forced expiratory volume in 1 second (FEV₁) were 11.5 and 54% predicted, respectively. Variables such as age, sex, Body Mass Index, comorbidities and exacerbation history showed no significant associations. Air quality (mean AQI: 71±10.7) did not influence outcomes (OR 1.018; 95% CI 0.949 to 1.092; p=0.622). Responders had higher baseline YPAS scores (OR 33.197; 95% CI 6.197 to 185.636; p<0.001) and greater FEV_₁ (OR 1.108; 95% CI 1.005 to 1.222; p=0.039).

AQI did not affect programme outcomes. Baseline sedentary status and FEV_₁ were key predictors of success. These findings support tailoring rehabilitation strategies to individual patient characteristics.