OBJECTIVES: To assess the effects of pursed-lip breathing (PLB) at rest on the behavior of heart rate (HR) and its variability, and on variations in blood pressure (BP), respiratory rate (RR) and pulse oxygen saturation (SpO2) in subjects with chronic obstructive pulmonary disease (COPD). METHODS: Sixteen subjects with COPD (seven in GOLD stage I, three in GOLD stage II and six in GOLD stage III; mean age 64±11 years; mean FEV1 60±25% of predicted value) were assessed at rest, in a seated position, under the following conditions: ten minutes of normal breathing without PLB (R1), eight minutes with PLB (R2) and ten minutes of normal breathing once more (R3). HR was recorded, beat-to-beat, by means of a Polar S810 heart monitor. The RMSSD index (root mean square of the difference between successive R-R intervals) was determined. BP, RR and SpO2 were also assessed during the trials. ANOVA for repeated measures followed by the Tukey test and Kruskal-Wallis test were used for data analysis, with a 5% significance level. RESULTS: There was a significant increase in the RMSSD index during R2, in comparison with R1. The HR variation between inspiration and expiration was 8.98 bpm, and the variation between HR at rest and HR with PLB was 8.25 bpm. During R2, RR decreased and SpO2 increased significantly in comparison with R1 and R3. BP values did not show significant changes. CONCLUSIONS: The results showed that PLB produced significant changes in HR, RR and SpO2, and did not alter BP in subjects with COPD. Furthermore, analysis of the RMSSD index showed that PLB promoted increased parasympathetic activity in these subjects, thus indicating that this technique influenced the autonomic cardiac modulation.
Chronic obstructive pulmonary disease; pursed-lip breathing; heart rate variability
