Blood flows to major organs were measured in conscious cats to study the changes in the distribution of cardiac output during voluntary static (isometric) exercise. Five animals were operantly conditioned to hold a bar against a fixed resistance for 30 s. Organ flows were measured during rest and exercise by injecting 25-μm radioactive microspheres into the left atrium or left ventricle. Increases were observed during exercise in heart rate (18%), mean arterial pressure (25%), left ventricular systolic pressure (17%), and rate of left ventricular development (26%). Static exercise produced significant changes in flow (ml.min-1.g-1) to the kidneys (-1.09 ± 0.24), spleen (-0.85 ± 0.21), and exercising muscles (+0.13 ± 0.08), while flows to liver, heart, brain, and nonexercising muscle were not significantly changed from control levels. Denervation of the left kidney abolished the decrease in flow to that kidney during exercise. Thus, static exercise appears to produce a significant increase in blood flow to exercising muscles and significant reduction in blood flow to spleen and kidneys. The reduction in renal blood flow is mediated by a neural mechanism.
|Original language||English (US)|
|Number of pages||5|
|Journal||Journal of Applied Physiology Respiratory Environmental and Exercise Physiology|
|State||Published - 1982|
ASJC Scopus subject areas