UBC Theses and Dissertations
Cardiovascular risk and autonomic changes during high and low affect provocations Lamensdorf, Angela Mona-Lisa
Does having a positive family history of essential hypertension predispose one to greater cardiovascular reactivity? Could reactivity be assessed with stress tasks that have greater external validity than traditional laboratory stressors? To answer these questions? 2b subjects with parental history of essential hypertension and 3b subjects without) were induced to converse with an experimenter on (a) a neutral topic (the weather)? and (b) an affective topic (a frustrating person or event). The topics were selected from a Iist of 2b because they had been rated by undergraduates as being the least and most arousing topics to talk about with a stranger in an experimental situation. The ratings yielded no interactions of sex of experimenter with sex of the subject. Subjects also performed a mental arithmetic task which is a standard laboratory stressor. The order of task presentation was randomly assigned within groups but matched across groups and sex to control sequence effects. For each subject? a 15-minute base I ine period was al lowed before each task. Readings of blood pressure? heart rate and rate of respiration were made at minute one? three? and five of each task phase. Each conversation task consisted of five minutes of talking followed by Iistening for five minutes to the experimenter. The tasks were separated by five-minute intervals to allow return to baseline levels. Results indicated that compared to individuals without parental history of hyper tension? individuals with parental history displayed higher levels of blood pressure (but not heart rate and rate of respiration) whether talking or listening. When peak values were considered; positive parental history subjects showed greater reactivity to the affective topic on diastolic blood pressure. The results also indicated that the three kinds of stressors yielded different levels of physiological responses with the math task and talk phase of the affect task yielding higher levels of blood pressure and heart rate than talk about the weather. The difference between the math and affective tasks was not significant on systolic blood pressure? but math yielded higher responses on heart rate and lower responses on diastolic blood pressure than talking about a frustrating event or person. These results suggest that a more generalizabIe stress stimulus such as an affect-laden conversation? can be reasonably standardized across subjects and elicits an aIpha-adrenergic vaso-constrictive response? a response more readily given by individuals with positive parental history than individuals without. The results also suggest that individuals with positive parental history of hypertension have higher blood pressure levels than individuals without. With respect to the similarity of the findings of this study? with those of other studies which have used older populations? it is proposed that these results are generalizable to older populations and provide evidence that a positive family history of essential hypertension may be considered a risk factor for later cardiovascular disease.
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