THE EFFECTS OF EXERCISE ON CENTRAL BLOOD VOLUME IN MAN

Abstract
The effect on central blood volume of 10 minutes of moderately heavy leg exercise in the supine position was studied in 10 normal subjects. Central blood volume was calculated by the Stewart-Hamilton formula from arterial dye-dilution curves following superior vena-caval or right atrial injection. During exercise the mean VO2 (O2 consumption in ml/min.) rose from 144 [plus or minus] 19.2 to 1011 [plus or minus] 217 ml/m2 and the cardiac index rose from a mean value of 3.42 [plus or minus] 0.81 to 7.99 [plus or minus] 1.02 liter/min./m2. Central blood volume increased by 141 to 745 ml in 8 subjects. For the entire group the increase in central blood volume averaged 285 ml. During 20 minutes of recovery the central blood volume declined in all 10 subjects by an average of 375 ml, with a fall ranging from 127 to 782 ml.