Ambulatory stress psychophysiology: the study of "compensatory and defensive counterforces" and conflict in a natural setting.

Thirty years ago, Donald Oken raised basic questions about psychophysiological research strategies for the study of the "psychological stress response" in the laboratory. Is it possible to simulate in the laboratory the situations one normally encounters? Do laboratory stimuli provoke affective arousal? Are different classes of stress stimuli associated with specific physiological response patterns? How do one's characteristic "defenses" and coping styles modulate one's responses? This paper describes a novel ambulatory research strategy in which the laboratory is moved into the natural setting. The advantages of this strategy are exemplified in studies of paramedics in whom 24-hour recordings were made of ambulatory blood pressure and heart rate. The ambulatory physiological data were then related to information about specific work location and subjective ratings of stress made in a diary at the time of each reading, objective assessments of the different stressful situations encountered, and the role of individual differences in anger expression and defensiveness in modulating these relationships. The findings illustrate the ability of real-life stressors to bring out relationships not typically obtained in the laboratory. Moreover, the natural setting permits individuals to respond to behavioral challenges using their preferred mode of coping with stress, as opposed to the constraints imposed on them in the laboratory. This research strategy has also helped uncover the significance of conflict about the expression of hostility, rather than hostility per se, as a key factor in the "stress response."