Blood Flow Regulation and Oxidative Stress During Submaximal Cycling Exercise in Patients with Cystic Fibrosis

Background:The impact of bloodflow regulation and oxidative stress during exercise in cysticfibrosis (CF) has yet to be investigated.Methods:A maximal graded exercise test was conducted to determine exercise capacity (VO2peak) and peak workload in 14 pediatric patientswith mild CF (age 14 ± 3 y, FEV193 ± 16 % predicted) and 14 demographically-matched controls. On a separate visit, participants performedsubmaximal cycling up to 60% of peak workload where brachial artery blood velocity was determined using Doppler ultrasound. Retrograde andantegrade components were further analyzed as indices of bloodflow regulation.Results:The cumulative AUC for retrograde velocity was lower in patients versus controls (1770 ± 554 vs. 3440 ± 522 cm,P= 0.038). In addition,an exaggerated oxidative stress response during exercise occurred in patients only (P= 0.004).Conclusion:These data suggest that patients with mild CF exhibit impaired bloodflow regulation and an exaggerated oxidative stress response tosubmaximal exercise.