In Vivo Quantification of Blood Flow and Wall Shear Stress in the Human Abdominal Aorta During Lower Limb Exercise

Magnetic resonance (MR) imaging techniques and a custom MR-compatible exercise bicycle were used to measure, in vivo, the effects of exercise on hemodynamic conditions in the abdominal aorta of eleven young, healthy subjects. Heart rate increased from 73±6.2 beats/min at rest to 110±8.8 beats/min during exercise (p < 0.0001). The total blood flow through the abdominal aorta increased from 2.9±0.6 L/min at rest to 7.2±1.4 L/min during exercise (p < 0.0005) while blood flow to the digestive and renal circulations decreased from 2.1±0.5 L/min at rest to 1.6±0.7 L/min during exercise (p < 0.01). Infrarenal blood flow increased from 0.9±0.4 L/min at rest to 5.6±1.1 L/min during exercise (p < 0.0005). Wall shear stress increased in the supraceliac aorta from 3.5±0.8 dyn/cm2 at rest to 6.2±0.5 dyn/cm2 during exercise (p < 0.0005) and increased in the infrarenal aorta from 1.3±0.8 dyn/cm2 at rest to 5.2±1.3 dyn/cm2 during exercise (p < 0.0005). © 2002 Biomedical Engineering Society.