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

ABSTRACT

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 (VO2 peak) and peak workload in 14 pediatric patients with mild CF (age 14±3y, FEV1 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.