Disparities between aortic and peripheral pulse pressures induced by upright exercise and vasomotor changes in man

Blood pressures were recorded simultaneously from the aortic arch and radial artery using two manometric systems with identical static and dynamic sensitivities. Measurements were made in four normal young men at rest and upright exercise requiring 29, 49, 78, and 100% of maximal oxygen uptake. Average radial arterial pressure rose from 133/66 mm Hg at rest to 236/58 mm Hg at maximal exercise. At the same time, average aortic pressures were 112/68 and 154/70 mm Hg, respectively. From rest to maximal exercise, pulse pressures at central and peripheral sites increased by factors of 1.95 and 2.60, respectively. Inducing reactive hyperemia in the arm abolished peripheral amplification. This amplification also diminished with time during prolonged heavy exercise. Mean pressures were nearly identical at the two sites at any oxygen uptake; mean pressures rose from 87 to 104 mm Hg from mild to maximal exercise. We conclude that estimates of stress on aortic and cerebral vessel walls and central baroreceptors would be grossly overestimated by use of peripheral pulse pressures.