[PP.38.09] Effects of Mild Dynamic Exercise on Circulatory and Autonomic Function in Healthy Volunteers

A New Radically Improved Model of the Circulation With Important Clinical Implications

“…These occur normally with exercise but, inappropriate change in SVR/conductance will upset DO 2 :VO 2 matching. We have shown that the normal increase in CO in mild to moderate exercise is virtually all driven by the increase in conductance (reduction in SVR) [19] See Figure 17. An important interaction between arterial blood pressure and the rate of cerebral oxygen delivery to the brain has recently been confirmed see (section 2).…”

“…It is important to realize that changes in blood flow can be a result of changes in peripheral resistance, especially at arteriolar level. When arterial pressure does not change, despite changes in VO 2 , say for example in mild-moderate exercise in normal subjects [19], the extra DO 2 is delivered entirely as a result of an increase in blood flow to the tissues, and this is due to tissue mediated reduction of SVR (mainly the resistance fall of the exercising muscle). By analogy, the variable flow of air supplying the pipes during performance in an ancient hydraulic organ, was sustained by a wind-chest kept at constant pressure by a water chamber.…”