Reduced blood flow in abdominal viscera measured by Doppler ultrasound during one-legged knee extension

The redistribution of blood flow (BF) in the abdominal viscera during right -legged knee extension-flexion exercise at very low intensity [peak heart r ate (HR), 76 beats/min] was examined by using Doppler ultrasound. While sit ting, subjects performed a right-legged knee extension-flexion exercise eve ry 6 s for 20 min. BF was measured in the upper abdominal aorta (Ao), right common femoral artery (RCFA), and left common femoral artery (LCFA). Visce ral BF (BFVis) was determined by the equation [BFAo - (BFRCFA + BFLCFA)] A comparison with the change in BF (Delta BF) preexercise showed a greater in crease in Delta BFRCFA than in Delta BFAo during exercise. This resulted in a reduction of BFVis to 56% of its preexercise value or a decrease in flow by 1,147 +/- 293 (+/-SE) ml/min at the peak workload. Oxygen consumption c orrelated positively with Delta BFAo, Delta BFRCFA, and Delta BFLCFA but in versely with Delta BFVis during exercise and recovery. Furthermore, BFVis ( % of preexercise value) correlated inversely with both an increase in HR (r = -0.89), and percent peak oxygen consumption (r = -0.99). This study demo nstrated that, even during very-low-intensity exercise (HR <90 beats/min), there was a significant shift in BF from the viscera to the exercising musc les.