Cardiovascular changes during the six-minute walk test in COPD patients

Abstract

Introduction: Specialised literature demonstrates that chronic obstructive pulmonary disease (COPD) has pathophysiological changes that impair cardiac autonomic function and the ability of the cardiovascular system to respond to stimuli. Objective: To analyze the correlation between heart rate (HR), peripheral oxygen saturation (SpO2), functional and pulmonary capacity in patients with COPD during the six-minute walk test (6MWT) before and after the pulmonary rehabilitation program (PRP). Methods: This is a descriptive and retrospective study, with collection carried out in the PRP database of a university in Vale dos Sinos, Brazil. Results: The sample consisted of 216 patients, classified as having severe COPD, with a predominance of males (57.4%), with a
mean age of 65.4 ± 7.9 years. The results showed that at the pre-PRP moment, the HR at the end of the test
showed a strong negative correlation (p < 0.01) with SpO2 obtained at the end of the test, and forced expiratory volume in the first second (FEV1). At the post-PRP moment, the HR at the end of the test was strongly negatively cor-related with SpO2 and FEV1 positively, weakly (p < 0.05) with the sensation of dyspnea at the end of the test, and strongly with the distance covered in the 6MWT (6MWD). Conclusion: The correlations between HR, FEV1, 6MWD, dyspnea and SpO2 were confirmed, making it evident that as the variables change, HR changes occur to meet the metabolic, oxygenation and ventilatory demands.