Inclusion criteria: 1. Children and adults (age >7 years, height >125cm , with CF and non CF bronchiectasis. 2. Completed a maximal CPET test according to accepted criteria; (maximal VO2 > 80% predicted, maximal heart rate > 80% predicted, acceptable RER (RER > 1.0 in children (under 18 years), RER > 1.05 for adults) or reaching a VO2 plateau .