Physical Training with Submaximal Intensities in Women II. Effect on Cardiac Output

In 13 women (age 21-61) circulatory studies at submaximal and maximal exercise were made before and after 7 weeks' training. For a given submaximal work load cardiac output was 1.5 1/min less in the older subjects. The maximal oxygen uptake increased through training from 1.94 1/min by 10.3% in the 9 younger and from 1.58 1/min by 6.3% in the older subjects. Maximal cardiac output increased from 14.3 1/min by 10.5 % in the younger and from 11.5 1/min by 8.7 % in the older. No change in the calculated maximal arterio-venous oxygen difference occurred. Intra-arterial blood pressure was lower after training in the middle-aged and older subjects at rest, during orthostatic tests, and during submaximal work. Small changes in cardiac output after training at rest and during orthostatic tests were not significant, although a lower heart rate was recorded.