Cardiovascular responses in the laboratory and in the natural environment: is blood pressure reactivity to laboratory-induced mental stress related to ambulatory blood pressure during everyday life?

Cardiovascular activity recorded at rest and during mental stress in the laboratory was studied in relation to ambulatory recorded cardiovascular activity at work and at home. Fifty-five Type A men (M = 42.4 years) underwent a standardized laboratory mental stress protocol in which systolic blood pressure, diastolic blood pressure, and heart rate were recorded at baseline and during a 15 min mental arithmetic task (MAT). On a subsequent day, ambulatory blood pressure and heart rate were recorded at 20 minute intervals for 12-14 hr during normal activities at home and at work. Subjects completed a behavioral diary concurrently with each cuff inflation. High and Low groups were identified based upon a median split of their cardiovascular response levels at baseline and during the MAT. Subjects with high systolic blood pressure levels during the MAT had high systolic blood pressure at home, at work, during physical activity, and when they reported being 'stressed'. Baseline systolic blood pressure in the laboratory was less consistently related to ambulatory systolic pressure across ambulatory conditions. Diastolic blood pressure at baseline was related to ambulatory diastolic blood pressure at work, at home, and when resting. Diastolic blood pressure during the MAT was associated with higher diastolic pressure at work and at home. Heart rate at baseline and during the MAT was related to heart rate at work and during physical activity. Change scores derived by subtracting mean values during the MAT from baseline resting levels were not associated with ambulatory blood pressures or heart rates under any daily conditions. In the best case, systolic blood pressure measured during the MAT was related to systolic blood pressure during physical activity, to systolic blood pressure and heart rate during mental stress, to systolic and diastolic blood pressure at rest, and to systolic blood pressure and heart rate at work but not at home. We conclude that levels of blood pressure and heart rate measured in the laboratory, but not reactivity (i.e, change scores) during the MAT, are related to blood pressure and heart rate levels recorded in the natural environment, especially in the work setting.