Exercise is beneficial for patients with cystic fibrosis (CF) but long-term effects of physical activity on lung function evolution are unknown. We evaluated the longitudinal relationship between changes in habitual physical activity (HPA) and rate of decline in lung function in patients with CF.We tracked HPA using the Habitual Activity Estimation Scale, forced expiratory volume in 1 s (FEV1) and Stage I exercise tests in 212 patients with CF over a 9-year period.Adjusting for sex, baseline age and FEV1, mucoid Pseudomonas aeruginosa and CF-related diabetes, mean¡SD FEV1 % predicted decreased by 1.63¡0.08% per year (p,0.0001) while mean¡SD HPA increased by 0.28¡0.03 h?day -1 per year (p,0.0001) over the study period. A greater increase in HPA was associated with a slower rate of decline in FEV1 (r50.19, p,0.0069). Dividing subjects into ''high'' and ''low'' activity (above or below the mean rate of change of activity, respectively), a steeper rate of FEV1 decline was observed for low (-1.90% per year) compared to high (-1.39% per year) (p50.002).Increases in HPA are feasible despite progression of lung disease and are associated with a slower rate of decline in FEV1, highlighting the benefit of regular physical activity, and its positive impact on lung function in patients with CF. @ERSpublications FEV1 declines at a lesser rate in patients with cystic fibrosis who increase their activity levels

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BackgroundPhysical activity (PA) and exercise have become an accepted and valued component of cystic fibrosis (CF) care. Regular PA and exercise can positively impact pulmonary function, improve physical fitness, and enhance health-related quality of life (HRQoL). However, motivating people to be more active is challenging. Supervised exercise programs are expensive and labour intensive, and adherence falls off significantly once supervision ends. Unsupervised or partially supervised programs are less costly and more flexible, but compliance can be more problematic. The primary objective of this study is to evaluate the effects of a partially supervised exercise intervention along with regular motivation on forced expiratory volume in 1 s (FEV1) at 6 months in a large international group of CF patients. Secondary endpoints include patient reported HRQoL, as well as levels of anxiety and depression, and control of blood sugar.Methods/designIt is planned that a total of 292 patients with CF 12 years and older with a FEV1 ≥ 35% predicted shall be randomised. Following baseline assessments (2 visits) patients are randomised into an intervention and a control group. Thereafter, they will be seen every 3 months for assessments in their centre for one year (4 follow-up visits). Along with individual counselling to increase vigorous PA by at least 3 h per week on each clinic visit, the intervention group documents daily PA and inactivity time and receives a step counter to record their progress within a web-based diary. They also receive monthly phone calls from the study staff during the first 6 months of the study. After 6 months, they continue with the step counter and web-based programme for a further 6 months. The control group receives standard care and keeps their PA level constant during the study period. Thereafter, they receive the intervention as well.DiscussionThis is the first large, international multi-centre study to investigate the effects of a PA intervention in CF with motivational feedback on several health outcomes using modern technology. Should this relatively simple programme prove successful, it will be made available on a wider scale internationally.Trial registrationClinicalTrials.gov Identifier: NCT01744561; Registration date: December 6, 2012.