CARDIOVASCULAR AND CATECHOLAMINE RESPONSES TO STATIC EXERCISE IN PARTIALLY CURARIZED HUMANS

Neural control of the circulation was evaluated during static exercise in 19 subjects by the determination of heart rate (HR), mean arterial pressure (MAP), cardiac output (CO) and plasma catecholamines. Influe nce from central command was evaluated during contractions with weaken ed muscles following partial curarization and reflex influence from me taboreceptors was assessed by post-exercise muscle ischaemia. Static h andgrip increased HR and more so MAP and CO and MAP remained elevated during post-exercise muscle ischaemia. With partial curarization plasm a catecholamines were also increased (P<0.05). Two-leg extension incre ased all Variables and during post-exercise muscle ischaemia elevation s of HR, MAP and CO were maintained (P<0.05). With partial curarizatio n HR, MAP and plasma noradrenaline were even greater during the contra ction. With the involvement of both legs during static exercise, refle x influence from the muscles elevated blood pressure by way of HR and CO and the importance of central command was detectable for HR and MAP as plasma catecholamines became elevated. However, the results indica te a separation between a central command influence on HR and CO relat ed to an increase in plasma catecholamines during a handgrip, while th e reflex influence on blood pressure was directed towards total periph eral resistance.