Exercise Capacity, Muscle Oxygenation, Respiratory Muscle Strength, and Physical Activity Level in Pediatric CF and PCD

Cystic fibrosis (CF) and primary ciliary dyskinesia (PCD) are genetic diseases characterized by chronic respiratory tract infections. In both diseases, impaired mucociliary clearance, recurrent respiratory infections, and persistent inflammation lead to progressive deterioration in respiratory function. This condition limits patients' activities of daily living, leading to physical inactivity and exercise intolerance. Functional exercise capacity in patients with CF and PCD is reduced due to increased respiratory load, musculoskeletal involvement, and nutritional deficiencies. In exercise tests involving the upper and lower extremities, both patient groups exhibited significantly lower performance compared to healthy individuals. Muscle oxygenation is particularly reduced in patients with cystic fibrosis and is associated with inadequate oxygen delivery to peripheral muscles, mitochondrial dysfunction, and increased muscle fatigue. Although studies on muscle oxygenation in PCD patients are limited, it is thought to be affected by similar pathophysiological mechanisms. Respiratory muscle strength is weakened in both patient groups due to chronic cough, hyperinflation, and increased respiratory effort. This is particularly evident in a significant decrease in inspiratory and expiratory muscle strength. The number of studies in the literature evaluating muscle oxygenation, respiratory muscle strength, and physical activity levels in patients with CF and PCD is limited. There are no studies comparing muscle oxygenation between patients with CF and PCD.