Pursed-lips breathing reduces dynamic hyperinflation induced by activities of daily living test in patients with chronic obstructive pulmonary disease: A randomized cross-over study.

BACKGROUND Dynamic hyperinflation leads to dyspnoea and consequent limitations in functional capacity in chronic obstructive pulmonary disease. It has been shown that the response to pursed-lips breathing in terms of dynamic hyperinflation and lower-limb exercise capacity is variable, and its effects on activities of daily living are unknown. This study aimed to evaluate the effect of pursed-lips breathing on dynamic hyperinflation and functional capacity in patients with chronic obstructive pulmonary disease in a lower-limb exercise test and in a multiple-task activities of daily living test. DESIGN Randomized cross-over study. PATIENTS Twenty-five patients with chronic obstructive pulmonary disease (16 men, mean age 64 ± 7 years, forced expiratory volume in 1 s (FEV1) = 41.7 ± 14.7% predicted). METHODS Patients randomly performed two 6-min walk tests (6MWT) with and without pursed-lips breathing (6MWT(PLB) and 6MWT(Non-PLB)) and two Glittre-ADL tests with and without pursed-lips breathing (TGlittre(PLB) and TGlittre(Non-PLB)). Inspiratory capacity was assessed at baseline and immediately after the tests. RESULTS The 6MWT(Non-PLB) and TGlittre(Non-PLB) induced similar magnitude dynamic hyperinflation (0.22 ± 0.24 l and 0.31 ± 0.23 l, respectively; p > 0.05). Pursed-lips breathing did not improve dynamic hyperinflation induced by the 6MWT (0.24 ± 0.20 and 0.22 ± 0.24 l, respectively, with and without pursed-lips breathing; p > 0.05). Dynamic hyperinflation in the TGlittre(PLB) was significantly lower than in the TGlittre(Non-PLB) (0.19 ± 0.20 l and 0.31 ± 0.23 l, respectively; p = 0.02). Pursed-lips breathing did not improve 6MWT or TGlittre performance. CONCLUSION Pursed-lips breathing reduced dynamic hyperinflation in the TGlittre, but not in the 6MWT. However, pursed-lips breathing did not improve functional capacity.