Heart-rate and blood-pressure responses to speech alone compared with cognitive challenges in the Stroop task.

Heart-rate and blood-pressure responses are assumed to reflect the "stressfulness" of cognitive tasks. Cardiovascular responses to speech are often assumed to be negligible. To test these assumptions, 34 middle-aged men (mean age 45.0 +/- 6.1) performed three versions of the Stroop color-conflict task, passive responding, push-button, and verbal. Although difficulty of passive responding was rated 11.8 (fairly light), push-button 16.1 (between hard and very hard), and verbal Stroop 14.5 (hard), all were significantly different. Analysis of variance showed during tasks heart-rate responses and systolic blood pressure did not differ. Recovery average heart-rate and over-all heart-rate patterns were not different for the difficult tasks but were significantly different from the easy task. Diastolic blood-pressure changes during tasks were more similar for verbal tasks despite the difference in difficulty. Stressor heart-rate and systolic blood-pressure responses did not reflect the difficulty of this stressful task. Verbalization of responses contributed significantly to cardiovascular reactivity.