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

Abstract

The redistribution of blood flow (BF) in the abdominal viscera during right-legged knee extension-flexion exercise at very low intensity [peak heart rate (HR), 76 beats/min] was examined by using Doppler ultrasound. While sitting, subjects performed a right-legged knee extension-flexion exercise every 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). Visceral BF (BF_Vis) was determined by the equation [BF_Ao − (BF_RCFA + BF_LCFA)]. A comparison with the change in BF (ΔBF) preexercise showed a greater increase in ΔBF_RCFA than in ΔBF_Ao during exercise. This resulted in a reduction of BF_Visto 56% of its preexercise value or a decrease in flow by 1,147 ± 293 (±SE) ml/min at the peak workload. Oxygen consumption correlated positively with ΔBF_Ao, ΔBF_RCFA, and ΔBF_LCFA but inversely with ΔBF_Vis during exercise and recovery. Furthermore, BF_Vis (% of preexercise value) correlated inversely with both an increase in HR ( r = −0.89), and percent peak oxygen consumption ( r = −0.99). This study demonstrated that, even during very-low-intensity exercise (HR <90 beats/min), there was a significant shift in BF from the viscera to the exercising muscles.