Feasibility and Impact of a Coached Home-Based Exercise Program on Cardiorespiratory Fitness in Adults With Cystic Fibrosis on Highly Effective Modulator Therapy.

BACKGROUND: In the era of highly effective modulator therapy (HEMT), people with cystic fibrosis (PwCF) are living longer and experiencing a shift in disease burden, with exercise emerging as an essential strategy to support cardiorespiratory and metabolic health. Despite known benefits, adherence to exercise remains low, and evidence guiding implementation of home-based interventions is limited. This study assessed the feasibility and clinical impact of a coached home-based exercise program in PwCF on HEMT. RESEARCH QUESTION: Does a personalized, coached home-based exercise program improve cardiorespiratory fitness in PwCF who are on stable HEMT? STUDY DESIGN AND METHODS: This randomized controlled pilot study enrolled PwCF on stable elexacaftor/tezacaftor/ivacaftor. Participants were randomized to a 12-week coached home-based exercise intervention or standard care. Intervention participants received weekly coaching and progressed to 180 min/wk of moderate-intensity exercise. Primary outcome was change in cardiorespiratory fitness measured by the Incremental Shuttle Walk Test. Secondary outcomes included adherence, changes in lung function (FEV1 % predicted), health-related quality of life (Cystic Fibrosis Questionnaire-Revised), perceived barriers to physical activity, and ventilation defect percent measured by hyperpolarized xenon-129 MRI scan. RESULTS: Twenty-one PwCF were enrolled, with 14 participants completing the study (intervention: n = 8; control: n = 6). The intervention group demonstrated a significant improvement in Incremental Shuttle Walk Test distance compared with the control group (76.3 ± 98.4 m vs -66.7 ± 93.3 m, respectively). The between-group difference favored the intervention by 14.3 m (95% CI, 2.96-25.63; P = .03). No significant changes were observed in FEV1 % predicted, Cystic Fibrosis Questionnaire-Revised total score, barrier scores, or ventilation defect percent. INTERPRETATION: Our results show that a personalized, coached home-based exercise program significantly improved cardiorespiratory fitness in PwCF on HEMT but had no measurable impact on lung function or quality of life. These findings support the feasibility of a home-based exercise coaching program. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov; No.: NCT05239611; URL: www.clinicaltrials.gov.