Studies on the Effect of Exercise on Cardiovascular Function

Abstract

For technical reasons, the measurement of cardiac output during brisk walking is difficult. By using a slight modification of the Hamilton dye-dilution method, such measurements, and measurements of mean circulation time, were made at rest and at the end of a moderate work load in normal subjects. A motor-driven treadmill was used for the exercise. It was found that the cardiac output increases 1.7 to 1.9 times and the mean circulation time decreases about 34 per cent in normal young men and women after a 10 minute walk at 3 miles per hour and 5 per cent grade.