Worry and heart rate variables: autonomic rigidity under challenge

[Borkovec, T. D. (1994). Worrying: perspectives on theory, assessment and treatment (pp. 5-34). West Sussex: Wiley] proposes that the cognitive activity of worry restricts autonomic nervous system activity, producing autonomic rigidity. Autonomic rigidity affects both sympathetic nervous system [Behav. Res. Ther. 28 (1990) 69.] and parasympathetic nervous system activity [Behav. Ther. 26 (1995) 457.]. Three experiments investigated the relationship between worry and autonomic system activity as indexed by heart activity measures. In the first experiment, we measured average heart rate when worriers were required to perform a public speaking task. No difference was found in heart rate between worriers and controls. The second and third experiments measured average heart rate and heart period variability (HPV) in worriers and controls during relaxation, non-stressful cognitive tasks, worried thinking, and aversive imagery conditions. There was no support for the autonomic rigidity view as worriers did not respond differently to non-worriers. These findings challenge the view that autonomic rigidity applies generally to worry.