The relations between respiratory muscles strengths and exercise capacity in patients with ankylosing spondylitis

Abstract

Ankylosing spondylitis is a chronic multisystem inflammatory disorder which mainly affects the joints of the axial skeleton. Significant reduction in exercise capacity due to pulmonary function impairment, chest wall restriction, peripheral muscle weakness, deconditioning and poor respiratory muscle performance was reported in the AS patients in previous studies. The aim of this study was to analyze the relations between the respiratory muscle strength and exercise capacity in patients with AS. The study included 39volunteer subjects (with a mean age of 38.00±11.35 years) who had AS diagnosis according to Modified New York criteria. Respiratory muscle strengths were assessed with maximal inspiratory (MIP) and expiratory (MEP) pressure measurements. The measurements were repeated 3 and the average was recorded. Exercise capacity was assessed with 6 minute walk test (6MWT). The average values of MIP and MEP were 66.94±20.76cmH2O and 73.46±34.12cmH2O, respectively. The result of 6MWT distance was found as 505.44±65.96m. A positive significant relation was found between MEP and exercise capacity (r=.398, p=.012). There was not a relationship between MIP and exercise capacity(r=.146, p=.376).As a result it was seen that there was a relationship between exercise capacity and MEP in AS patients. There are some studies showing the relationship between respiratory muscle strength and exercise capacity. But the contribution of respiratory muscle performance still remains questionable for the reduction of exercise capacity in patients with ankylosing spondylitis. Further studies including more extensive measurements such as VO2max, with higher population are needed.