Avramidou V, et al. - The inter-relations between outcome measures of multiple breath washout (MBW) and cardiopulmonary exercise testing (CPET) were gauged during this trial. Furthermore, it ascertained if ventilation inhomogeneity speculated the exercise intolerance. A connection was established between the ventilation inhomogeneity as indicated by increased LCI with less efficient ventilation during strenuous exercise. It exerts a negative effect on the exercise capacity in CF.