Although some patients reported lower ratings of perceived breathlessness and leg fatigue at the selleck chemicals llc end of exercise with conical-PEP, this was not a consistent observation and, on average, there were no differences between conical-PEP and control interventions. However, it should be noted that the exercise protocol was designed to be symptom limited and so it is to be expected that the patients would naturally continue exercising until their symptoms reached similar values

in the different protocols. The finding that conical-PEP breathing significantly improved inspiratory capacity and slow vital capacity confirms that it has a real effect on exercise-induced hyperinflation. The fact that this carried over to a strong trend in exercise endurance suggests that it was probably a key element in determining volitional fatigue during the exercise test. It is reasonable that the significant improvement

in hyperinflation did not carry over to a significant difference in endurance time CAL-101 datasheet because many factors affect the point of volitional fatigue. In addition to breathlessness, which is the main interest here, leg muscle fatigue, pains and sensations associated with joints and tendons, and an increase in body temperature, as well as boredom, may all contribute. The finding that inspiratory capacity did not change during exercise in

the control intervention was whatever surprising but may reflect the fact that these patients had only moderate airflow obstruction. Therefore the lung hyperinflation might have been reduced by bronchodilator administration prior to the protocol and the exercise did not exacerbate the degree of hyperinflation that may have existed at rest. A useful control would have been to test the effect of conical-PEP on these patients at rest where we would anticipate that they would show a similar increase in inspiratory capacity. Exercise training is the key component of pulmonary rehabilitation programs for chronic obstructive pulmonary disease but is often limited by early exercise-induced dyspnoea aggravated by dynamic hyperinflation (O’Donnell and Webb 2008). Pharmaceutical approaches (O’Donnell et al 2004) and non-invasive CPAP have been suggested as ways of minimising dynamic hyperinflation. Conical-PEP, a very simple and cheap device, was effective in reducing dynamic hyperinflation. It also has the potential to be used in a wide range of activities since it is not limited by a power supply. Conical-PEP may have the potential for use as an economical and non-invasive tool for increasing exercise in a pulmonary rehabilitation program in this population. While the results are encouraging, there a number of limitations to this study.