Skeletal Muscle Physiology and Exercise Capacity in Patients with Chronic Obstructive Pulmonary Disease at Ahmadu Bello University Teaching Hospital, Zaria

Chronic obstructive pulmonary disease reduces exercise capacity through both ventilatory limitation and skeletal muscle dysfunction, yet the relative contributions of these mechanisms have not been empirically examined in Nigerian clinical populations. This study assessed skeletal muscle function and exercise capacity in patients with chronic obstructive pulmonary disease at Ahmadu Bello University Teaching Hospital, Zaria, Kaduna State, North West Nigeria. A cross-sectional comparative design enrolled 60 confirmed chronic obstructive pulmonary disease patients and 30 age-matched healthy controls. Spirometry confirmed airflow obstruction staging. Skeletal muscle function was assessed by handgrip dynamometry and quadriceps strength using a portable dynamometer. Exercise capacity was measured using the six-minute walk test, and peripheral oxygen saturation was monitored throughout. Multiple regression and ANOVA were applied. Results showed that patients had significantly reduced quadriceps and handgrip strength compared to controls. Six-minute walk distance was significantly lower in patients and declined with increasing disease severity. Quadriceps strength was a stronger predictor of walk distance than forced expiratory volume in one second, suggesting extrapulmonary muscle limitation as a dominant exercise constraint. This study addresses a literature gap on the relative physiological determinants of exercise limitation in Nigerian chronic obstructive pulmonary disease patients. Pulmonary rehabilitation incorporating peripheral muscle strengthening is strongly recommended. Keywords: chronic obstructive pulmonary disease, skeletal muscle, exercise capacity, six-minute walk, Zaria.