Correlation of exercise capacity to respiratory muscle strength and pulmonary function in children with cystic fibrosis: a cross-section study

Cystic fibrosis (CF) represents a genetic inherited disorder that impacts many systems, but most profoundly the respiratory and digestive systems. Children suffering from CF experience deterioration in different life aspects because of pulmonary dysfunction, weak respiratory musculature, and low exercise capacity. This study aimed to compare pulmonary function, respiratory muscle strength, and exercise capacity between pediatric patients with CF and their healthy counterparts, while also investigating the correlations among these variables within each group. This cross-sectional study enrolled 52 pediatric participants (26 diagnosed with CF and 26 age-matched healthy controls) between 8 and 12 years of age at Abu El Rish Children’s hospital, Cairo University. Both groups were assessed and compared regarding pulmonary function using spirometry (FEV₁, FVC, FEV₁/FVC, PEF), respiratory muscle strength via manometry (MIP, MEP), and exercise capacity through the Six-Minute Walk Test (6MWT). Data analysis employed unpaired t-tests alongside Pearson correlation coefficients, establishing statistical significance at p < 0.05. CF affected children exhibited significantly lower FEV₁, FVC, PEF, MIP, MEP, and 6MWT distances relative to healthy comparison subjects (p = 0.001). In children with CF, MIP demonstrated an inverse correlation with PEF (r = -0.447, p = 0.02), and MEP showed positive correlation with FEV₁/FVC (r = 0.481, p = 0.01). Correlational analyses between 6MWT and pulmonary function parameters were not significant in both groups. BMI demonstrated a positive correlation with 6MWT among patients with CF. The pulmonary function, muscular strength, and exercise tolerance of children with CF are significantly lower compared to peers without the condition. Improvement in clinical results of children with CF require an integrated strategy comprising respiratory muscle reconditioning, monitored exercise therapy, and nutritional management.