Changes in Cardiac Output with Age

In the first of two papers, the details and results of a systematic, carefully standardized application of dye dilution technic to the measurement of cardiac output are reported. A substantially reduced output was a consistent finding in older subjects. Factors responsible for this are analyzed in this article, and further interpretations are made in the succeeding article. One result of the analysis of time-concentration curves of dye provides an interesting relationship to clinical estimates of circulation time.