The degree of abdominal blood flow redistribution during exercise is poorly understood. In order to investigate the regional hemodynamic responses of abdominal arteries at the onset of exercise, eight female subjects (21-30 yrs) performed semi-supine cycle ergometry at 40 W for 4 min. Blood velocity (BV) in the right renal (RA), superior mesenteric (SMA), and splenic (SA) arteries was measured by the pulsed echoDoppler ultrasonography throughout the protocol, with heart rate (HR) and mean arterial pressure (MAP) measured beat-by-beat using Finapres. Vascular resistance index (RI) in each artery was calculated from BV/MAP. MAP and HR increased significantly during exercise compared to the resting baseline (MAP; 76±9 to 83±8 mmHg, HR; 60±7 to 101±9 bpm at 4 min). The BV of RA and SA decreased rapidly and exponentially after the onset of exercise (change in BV at 30 s; -19±5 and -19±12 %, respectively), reaching -27±7 and -27±15 % of baseline by end exercise (4 min). RI remained constant during the initial 30 s of exercise (reflecting a reduction in MAP) and then increased towards the end of exercise (change in RI at 4 min; +55±21 and +59±39 %, respectively). In contrast, both BV and RI in the SMA remained constant throughout the protocol. We conclude that low-intensity cycling exercise resulted in differential blood flow responses in arteries supplying the abdominal organs.

DESCENTE SPORTS SCIENCE Vol.28/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE