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Keywords:

  • Test-retest reliability;
  • Cardiovascular reactivity;
  • Ambulatory BP monitoring;
  • Beta-adrenergic stimulation;
  • Cold-pressor test

ABSTRACT

The mental stress test protocol is used extensively in research, but different laboratories often employ different stress tasks, utilize different dependent variables to index the stress response, and perform different transformations on the gathered data. The present study determined the test-retest reliability of 11 cardiovascular dependent variables during a resting baseline and three common stress tasks: playing a video game, performing a choice reaction-time test, and performing a cold-pressor test. Sixty healthy, middle-aged males underwent testing twice, approximately three months apart. Instructions were delivered via videotape and data were gathered on-line by computer to ensure a standard laboratory environment. Each task elicited significant increases in blood pressure, vascular rigidity, LVET, heart rate, and stroke volume. In addition, the cold-pressor test led to increases in total systemic resistance and mean systolic ejection rate. The absolute levels of the 11 dependent variables were correlated across tasks (partial r, baseline removed, = .06 to .69, 32 of 33 comparisons significant at p<.05), indicating that reactivity to stress generalizes across alternate test forms. The absolute levels also showed significant test-retest reliability (r= .32 to .82; 40 of 44 comparisons significant at p<.05). In addition, for 19 of 33 comparisons, absolute levels showed greater test-retest reliability than change scores derived by subtracting the initial resting baseline value from the stress-task value. Finally, blood pressures taken during the stress tests were more highly correlated with the average blood pressures measured via ambulatory monitoring than casual office pressures, suggesting that such stress values may more accurately reflect average blood pressure.