Effect of Exercise on Cerebral Circulation

Abstract

The effect of supine physical exercise on cerebral blood flow (CBF) was measured in 30 normal subjects with the ¹³³Xe inhalation technique. The CBF measurements were correlated to changes in Pco₂, heart rate, and blood pressure, and to cardiac output and right atrial pressure in 10 of the subjects who underwent Swan-Ganz catheterization. No significant change was found in CBF during physical exercise, although a marked increase in cardiac output, blood pressure, and right atrial pressure and a mild decrease in PCO₂ were found. Cerebrovascular resistance increased by 38%, in contrast to a decrease of 33% in the peripheral vascular resistance. The factors that affect the mechanism of cerebrovascular autoregulation during exercise are discussed.