Expiratory flow limitation, air-trapping and hyperinflation are well-known problems in COPD patients. Due to dyspnea during exercise COPD patients often avoid physical activity, which is one of the most important parameters of quality of life. In studies with long-acting bronchodilators, e.g., the anticholinergic agent tiotropiumbromide, a reduction of expiratory flow limitation, hyperinflation and dyspnea could be demonstrated. This was followed by an increase in physical activity. Increase in inspiratory capacity and reduction of functional residual capacity correlated well with the improvement of exercise capacity. In conclusion, bronchodilators such as tiotropiumbromide are able to reduce hyperinflation in COPD patients.