All patients received regular treatment consisting of inhaled bronchodilators and steroids and the dosage did not changed during the study. The study protocol was approved by the Institutional Ethics Committee and all patients signed a written consent form prior to study initiation (109/2006). The target number of patients was calculated to be 10 patients in each group, based on a 5% type I error, a 2-sided test, and an 80% power to detect a change between the groups in 5 to SD2 at rest. Considering a drop out of 20%, 12 patients in each group were calculated. Due to the Gaussian distribution and/or homogeneity of variance in variable values, parametric tests were selected for statistical analysis.