Abstract
Cardiac rate-variability control and an initial demonstration of systolic blood-pressure variability control using visual feedback of physiological information were examined. Continuous measures of respiration, heart rate, EXG waveform analysis, and systolic blood pressure were obtained for both experimental groups and for yoked controls who saw the same visual display as the experimental Ss. Ss successful at reducing heart-rate variability showed clear changes in the P-R wave relationships of the EKG, indicating possible direct attempts to manipulate heart rate so as to reduce variability. Ss controlling blood-pressure variability who had high heart rates were more successful in reducing variability than those with low rates, possibly because of differential feedback to Ss with high and low heart rates. In addition, apparently as a reaction to E's adjustment of the visual target range, experimental Ss showed decreases in mean blood-pressure levels.