Effects of epinephrine on cardiovascular and metabolic responses to leg exercise in man

¹ Mayo Clinic and Mayo Foundation, Rochester, Minnesota

In studies on six experienced subjects lying supine, cardiac output and oxygen content of femoral venous blood were measured with the subject at rest, during the increase in muscle blood flow caused by intravenous infusion of epinephrine, during mild leg exercise, and during identical exercise combined with an infusion. The oxygen content of the blood from the exercising limb was much higher (average, 50%) during an infusion than when no infusion was given (average, 32%). The mean increase in cardiac output during the combined maneuver (8.2 liters/min) almost equaled the sum of the increases during the separate infusion (3.7 liters) and during exercise (4.7 liters). All individual studies showed approximately this same result. Thus, the additional blood supplied to the leg muscles by the infusion did not appear to be used for metabolic purposes during exercise.

Submitted on March 22, 1963