Psychophysiological responses in panic and stress

This paper examines the use of ambulatory monitoring in investigating individual differences in physiological functioning during everyday life and the relationship between psychophysiological responses in the laboratory and in the field. Techniques for dealing with confounding variables and analysing the ambulatory data are described. Findings from a study of young volunteers indicated that average cardiovascular responses to specific laboratory tasks did not relate consistently to measures of heart rate responsiveness in the field. However, measures derived from peak cardiovascular responses to a battery of active coping challenges did reliably predict cardiac responsiveness in real life, particularly when non-psychological factors influencing cardiac reactivity were taken into account. These measures may reflect reliable and generalizable differences in the extent of sympathetic activation in response to stress. These findings were largely replicated in a study of panic patients. The peak heart rate response to a battery of psychological stressors was the strongest predictor of heart rate variability in the field. This study also found that panic patients exhibited greater cardiac variability during everyday life than normal controls, suggesting that panic patients may be experiencing more frequent and intense fluctuations in bodily function. Such a propensity may contribute to the increase in perceived body sensations reported by panic patients.