Studies of Human Organ System Function 85 



significant redistribution of this resistance, or both. Especially 

 in association with a decrease in cardiac output, an agewise 

 increase in mean arterial pressure inferred from systolic and 

 diastolic values (Master, Dublin and Marks, 1950) would 

 indicate an increase in total resistance; thus, the inter- 

 relationship of output and pressure provides for an evaluation 



10 



20 



30 



80 90 



40 50 60 



Age years 

 Fig. 6. The relation between cardiac output and age in 67 "normal 



of peripheral circulatory performance. Determinations of 

 cardiac output were made in 67 males between the ages of 19 

 and 86 years of age by an indicator dilution method. Accord- 

 ing to clinical criteria, these subjects were free of suspected 

 relevant disease, and they form the basis for an agewise 

 analysis of change. The basal cardiac output averaged 5-08 

 l./min. with a standard deviation of 1-51 l./min. Fig. 6 



