Several strategies may potentially reduce DH and, consequently, increase exercise tolerance
in COPD patients. Among them hyperoxia, therapy using bronchodilators, heliox and physical conditioning
can be found. In addition to these strategies, some studies suggest that pursedlip breathing (PLB) may help to reduce DH.
PLB acts on the breathing pattern by prolonging expiration, reducing the functional residual capacity (FRC) and improving the ventilatory efficiency. Visser et al. observed an increase in inspiratory capacity (IC) in COPD patients at rest
while performing PLB, indicating a reduction in pulmonary hyperinflation. Bianchi et al. reported
that PLB was able to reduce the chest wall volume at end expiration in COPD patients at rest,mainly due to a reduction in the volume of the abdominal compartment. The patients with a greater
degree of airway obstruction and more severe hyperinflation at rest were those who benefited from
this strategy. However, we found no evidence that PLB can improve the breathing pattern or reduce
DH in COPD patients during highintensity exercise.