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

Introduction Specialised literature demonstrates that chronic obstructive pulmonary disease (COPD) has patho-physiological 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.