Blood flow regulation and oxidative stress during submaximal cycling exercise in patients with cystic fibrosis

Background The impact of blood flow regulation and oxidative stress during exercise in cystic fibrosis (CF) has yet to be investigated. Methods A maximal graded exercise test was conducted to determine exercise capacity (VO 2 peak) and peak workload in 14 pediatric patients with mild CF (age 14±3y, FEV 1 93±16 % predicted) and 14 demographically-matched controls. On a separate visit, participants performed submaximal cycling up to 60% of peak workload where brachial artery blood velocity was determined using Doppler ultrasound. Retrograde and antegrade components were further analyzed as indices of blood flow regulation. Results The cumulative AUC for retrograde velocity was lower in patients versus controls (1770±554 vs. 3440±522cm, 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 blood flow regulation and an exaggerated oxidative stress response to submaximal exercise.