Efeitos de um programa de treinamento de endurance em paciente com doença pulmonar obstrutiva crônica: um estudo experimental de caso único

Abstract

The minimum duration of exercise training program in patients with Chronic Obstructive Pulmonary Disease (COPD) is not established and has been poorly investigated. In this way, the aim of this study was to document, over time, lower-limb endurance training program effects in a patient with COPD, evaluating the minimum time necessary for occurring changes in exercise capacity and if these changes stabilize during intervention period. It was conducted a single-subject design with two phases (baseline and intervention), with repeated measurements of studied variables for six and 12 weeks, respectively. A patient with 73 years old and severe COPD, according to Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease, was studied. A metabolic analyzer system was used to evaluate the participant, at regular intervals, during incremental, symptom-limited cycle ergometer exercise test. In the intervention phase, the training consisted of exercise on a cycle ergometer three times a week during 12 weeks. The exercise intensity was set at 70% of the average baseline peak work rates. Peak exercise variables and responses to identical levels of work rate were studied. The statistical methods used were visual analysis, associated with Kappa statistic, two-standard deviation band and regression analysis. Significance was accepted at the p<0.05 level. Peak exercise variables as work rate, oxygen uptake (VO2), carbon dioxide output and ventilation (VE) increased while VE, Borg score and heart rate/maximum predicted heart rate relationship decreased at an identical level of work rate. The changes in exercise capacity verified by VE, VO2 and Borg score analysis were observed after four weeks of training. Moreover, these variables, besides respiratory frequency, showed significant decrease in the course of intervention phase, while tidal volume and peripheral oxygen saturation increased during this phase. In conclusion, the assessed participant increased his exercise tolerance after a lower-limb endurance training program that was consistent with pulmonary rehabilitation studies. The observed changes in important variables related to exercise capacity initiated after four weeks of intervention beginning and continued, without stabilization, until the end of the 12 weeks training program.