ANXIETY AND AUTONOMIC FLEXIBILITY - A CARDIOVASCULAR APPROACH

Autonomic characteristics of panickers, blood phobics, and nonanxious controls were compared with a variety of cardiovascular measures: incl uding spectral analysis of the cardiac inter-beat interval time series (derived from the electrocardiogram). Responses to laboratory stresso rs (shock avoidance and cold face stress) of 16 participants who repor ted recent occurrences of frequent severe panic attacks, 15 participan ts who reported strong somatic reactions and fainting to the sight of blood, and 15 controls, were recorded. Results suggested distinct auto nomic patterns among the three groups. Across conditions, panickers di splayed the highest heart rates (HR) coupled with the least HR variabi lity, which indicates low levels of cardiac vagal tone. Blood phobics showed more vagally mediated HR variability than panickers, with a sig nificant association between cardiac rate and mean arterial pressure. Controls generally showed the most HR variability and 'spectral reserv e' (a quality that indicates flexible responsivity). Results are discu ssed in the context of traditional models of anxiety and autonomic act ivity in contrast to contemporary notions of stability and change in b iological systems. (C) 1998 Elsevier Science B.V. All rights reserved.