A comparison of psychologically-induced cardiovascular reactivity in laboratory and natural environments.

This study focused on the possible role of heart rate reactivity in the development of essential hypertension in female subjects. Baseline heart rate, systolic and diastolic blood pressures, taken over a 6 week period, were used for comparison with the same measures taken during a laboratory session involving relaxation, cold pressor, mental arithmetic and exercise, and before and after an academic examination. Information about personality and lifestyle was included in subsequent univariate and multivariate analyses. Significant increases were produced in heart rate by the mental arithmetic task (p less than 0.00005), in systolic pressure by the exercise task (p less than 0.00005) and in systolic pressure prior to the examination (p less than 0.001). No significant diastolic effects were found. When subjects were divided into high and low reactors, on the basis of their heart rate reactivity to mental arithmetic, there was little difference in cardiovascular activity between the groups in any other condition. Significant effects on reactivity were found for diet, regular daily exercise and type A personality. The results are discussed in terms of Obrist's theory of the genesis of essential hypertension.