Age differences in the consistency of cardiovascular response patterns in healthy women

To determine if response consistency is higher in older women, twenty young adult (mean = 20 years) and twenty-two elderly (mean = 82 years) women participated in a 20-min stress protocol including serial subtraction, anxiety and anger imagery tasks. All subjects were healthy and free of diagnosed cardiovascular disease. Heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) responses to the tasks were assessed. To allow comparisons of the effects of stress on different cardiovascular parameters, all baseline-stress change scores were converted to z-scores. Forty-two 3(parameter)X3(stressor) matrices of z-scores, one for each subject, were created. Intraclass correlations computed using these matrices revealed greater consistency of response hierarchies (e.g., DBP greater than SBP greater than HR) among elderly subjects. Possible mechanisms for this effect are discussed.